@c This is part of the Emacs manual.
-@c Copyright (C) 1985,86,87,93,94,95,97,99,2000 Free Software Foundation, Inc.
+@c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 1999, 2000,
+@c 2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
@c See file emacs.texi for copying conditions.
@node Programs, Building, Text, Top
@chapter Editing Programs
@cindex C editing
@cindex program editing
- Emacs has many commands designed to understand the syntax of programming
-languages such as Lisp and C. These commands can:
+ Emacs provides many features to facilitate editing programs. Some
+of these features can
@itemize @bullet
@item
-Move over or kill balanced expressions or @dfn{sexps} (@pxref{Lists}).
+Find or move over top-level definitions (@pxref{Defuns}).
@item
-Move over or mark top-level expressions---@dfn{defuns}, in Lisp;
-functions, in C (@pxref{Defuns}).
+Apply the usual indentation conventions of the language
+(@pxref{Program Indent}).
@item
-Show how parentheses balance (@pxref{Matching}).
+Balance parentheses (@pxref{Parentheses}).
@item
Insert, kill or align comments (@pxref{Comments}).
@item
-Follow the usual indentation conventions of the language
-(@pxref{Program Indent}).
+Highlight program syntax (@pxref{Font Lock}).
@end itemize
- Emacs commands that operate on words, sentences and paragraphs are
-very useful in editing code even though their canonical application is
-for editing human language text. Most symbols contain words
-(@pxref{Words}); sentences can be found in strings and comments
-(@pxref{Sentences}). Paragraphs per se don't exist in code, but the
-paragraph commands are useful anyway, because programming language major
-modes define paragraphs to begin and end at blank lines
-(@pxref{Paragraphs}). Judicious use of blank lines to make the program
-clearer will also provide useful chunks of text for the paragraph
-commands to work on.
-
- The selective display feature is useful for looking at the overall
-structure of a function (@pxref{Selective Display}). This feature
-hides the lines that are indented more than a specified amount.
-Programming modes often support Outline minor mode (@pxref{Outline
-Mode}). The Foldout package provides folding-editor features
-(@pxref{Foldout}).
-
- The ``automatic typing'' features may be useful for writing programs.
-@xref{Top,,Autotyping, autotype, Autotyping}.
+ This chapter describes these features and many more.
@menu
* Program Modes:: Major modes for editing programs.
-* Lists:: Expressions with balanced parentheses.
-* List Commands:: The commands for working with list and sexps.
-* Defuns:: Each program is made up of separate functions.
- There are editing commands to operate on them.
+* Defuns:: Commands to operate on major top-level parts
+ of a program.
* Program Indent:: Adjusting indentation to show the nesting.
-* Matching:: Insertion of a close-delimiter flashes matching open.
+* Parentheses:: Commands that operate on parentheses.
* Comments:: Inserting, killing, and aligning comments.
-* Balanced Editing:: Inserting two matching parentheses at once, etc.
-* Symbol Completion:: Completion on symbol names of your program or language.
-* Which Function:: Which Function mode shows which function you are in.
+* Documentation:: Getting documentation of functions you plan to call.
* Hideshow:: Displaying blocks selectively.
+* Symbol Completion:: Completion on symbol names of your program or language.
* Glasses:: Making identifiersLikeThis more readable.
-* Documentation:: Getting documentation of functions you plan to call.
-* Change Log:: Maintaining a change history for your program.
-* Authors:: Maintaining an @file{AUTHORS} file.
-* Tags:: Go direct to any function in your program in one
- command. Tags remembers which file it is in.
-* Imenu:: Making buffer indexes as menus.
-* Emerge:: A convenient way of merging two versions of a program.
+* Misc for Programs:: Other Emacs features useful for editing programs.
* C Modes:: Special commands of C, C++, Objective-C,
Java, and Pike modes.
-* Fortran:: Fortran mode and its special features.
* Asm Mode:: Asm mode and its special features.
+@ifnottex
+* Fortran:: Fortran mode and its special features.
+@end ifnottex
@end menu
@node Program Modes
@section Major Modes for Programming Languages
-
@cindex modes for programming languages
+
+ Emacs has specialized major modes for various programming languages.
+@xref{Major Modes}. A programming language major mode typically
+specifies the syntax of expressions, the customary rules for
+indentation, how to do syntax highlighting for the language, and how
+to find the beginning of a function definition. It often customizes
+or provides facilities for compiling and debugging programs as well.
+
+ Ideally, Emacs should provide a major mode for each programming
+language that you might want to edit; if it doesn't have a mode for
+your favorite language, you can contribute one. But often the mode
+for one language can serve for other syntactically similar languages.
+The major mode for language @var{l} is called @code{@var{l}-mode},
+and you can select it by typing @kbd{M-x @var{l}-mode @key{RET}}.
+@xref{Choosing Modes}.
+
@cindex Perl mode
@cindex Icon mode
-@cindex Awk mode
@cindex Makefile mode
@cindex Tcl mode
@cindex CPerl mode
@cindex Metafont mode
@cindex Modula2 mode
@cindex Prolog mode
+@cindex Python mode
@cindex Simula mode
@cindex VHDL mode
@cindex M4 mode
@cindex Shell-script mode
@cindex Delphi mode
@cindex PostScript mode
- Emacs also has major modes for the programming languages Lisp, Scheme
-(a variant of Lisp) and the Scheme-based DSSSL expression language, Ada,
-Awk, C, C++, Delphi (Object Pascal), Fortran (free and fixed format),
-Icon, IDLWAVE,
-Java, Metafont (@TeX{}'s companion for font creation), Modula2,
-Objective-C, Octave, Pascal, Perl, Pike, PostScript, Prolog, Simula,
-VHDL, CORBA IDL, and Tcl.
-There is also a major mode for makefiles, called Makefile
-mode. An alternative mode for Perl is called CPerl mode. Modes
-are available for scripts for the common Unix shells, VMS DCL and
-MS-DOS/MS-Windows @samp{BAT} files. In a similar fashion to programming
-languages, modes are provided for editing various sorts of configuration
+@cindex Conf mode
+@cindex DNS mode
+ The existing programming language major modes include Lisp, Scheme (a
+variant of Lisp) and the Scheme-based DSSSL expression language, Ada,
+ASM, AWK, C, C++, Delphi (Object Pascal), Fortran (free format and fixed
+format), Icon, IDL (CORBA), IDLWAVE, Java, Metafont (@TeX{}'s
+companion for font creation), Modula2, Objective-C, Octave, Pascal,
+Perl, Pike, PostScript, Prolog, Python, Simula, Tcl, and VHDL. An
+alternative mode for Perl is called CPerl mode. Modes are available for
+the scripting languages of the common GNU and Unix shells, VMS DCL, and
+MS-DOS/MS-Windows @samp{BAT} files. There are also major modes for
+editing makefiles, DNS master files, and various sorts of configuration
files.
-Separate manuals are available for the modes for Ada (@pxref{Top, , Ada
-Mode, ada-mode, Ada Mode}), C/C++/Objective C/Java/Corba IDL
-(@pxref{Top, , CC Mode, ccmode, CC Mode}) and the IDLWAVE modes
-(@pxref{Top, , IDLWAVE, idlwave, IDLWAVE User Manual}).
-
- Ideally, a major mode should be implemented for each programming
-language that you might want to edit with Emacs; but often the mode for
-one language can serve for other syntactically similar languages. The
-language modes that exist are those that someone decided to take the
-trouble to write.
-
- There are several forms of Lisp mode, which differ in the way they
-interface to Lisp execution. @xref{Executing Lisp}.
-
- Major modes for programming languages usually provide conveniency
-features such as syntax-sensitive indentation, syntax highlighting
-(@pxref{Font Lock}), movement by blocks and functions, etc.
-
- Each of the programming language major modes defines the @key{TAB} key
-to run an indentation function that knows the indentation conventions of
-that language and updates the current line's indentation accordingly.
-For example, in C mode @key{TAB} is bound to @code{c-indent-command}.
-@kbd{C-j} is normally defined to do @key{RET} followed by @key{TAB};
-thus, it too indents in a mode-specific fashion.
-
@kindex DEL @r{(programming modes)}
@findex c-electric-backspace
- In most programming languages, indentation is likely to vary from
-line to line. So the major modes for those languages rebind @key{DEL}
-to treat a tab as if it were the equivalent number of spaces (using
-the command @code{c-electric-backspace}). This makes it possible to
-rub out indentation one column at a time without worrying whether it
-is made up of spaces or tabs. Use @kbd{C-b C-d} to delete a tab
-character before point, in these modes.
-
- Programming language modes define paragraphs to be separated only by
-blank lines, so that the paragraph commands remain useful. Auto Fill mode,
-if enabled in a programming language major mode, indents the new lines
-which it creates.
-
- @xref{Choosing Modes}, for the description of how major modes are
-activated.
+ In most programming languages, indentation should vary from line to
+line to illustrate the structure of the program. So the major modes
+for programming languages arrange for @key{TAB} to update the
+indentation of the current line. They also rebind @key{DEL} to treat
+a tab as if it were the equivalent number of spaces; this lets you
+delete one column of indentation without worrying whether the
+whitespace consists of spaces or tabs. Use @kbd{C-b C-d} to delete a
+tab character before point, in these modes.
+
+ Separate manuals are available for the modes for Ada (@pxref{Top, , Ada
+Mode, ada-mode, Ada Mode}), C/C++/Objective C/Java/Corba IDL/Pike/AWK
+(@pxref{Top, , CC Mode, ccmode, CC Mode}) and the IDLWAVE modes
+(@pxref{Top, , IDLWAVE, idlwave, IDLWAVE User Manual}). For Fortran
+mode, see
+@iftex
+@ref{Fortran,,, emacs-xtra}.
+@end iftex
+@ifnottex
+@ref{Fortran}.
+@end ifnottex
+
@cindex mode hook
@vindex c-mode-hook
@vindex emacs-lisp-mode-hook
@vindex lisp-interaction-mode-hook
@vindex scheme-mode-hook
- Turning on a major mode runs a normal hook called the @dfn{mode hook},
-which is the value of a Lisp variable. Each major mode has a mode hook,
-and the hook's name is always made from the mode command's name by
-adding @samp{-hook}. For example, turning on C mode runs the hook
-@code{c-mode-hook}, while turning on Lisp mode runs the hook
-@code{lisp-mode-hook}. @xref{Hooks}.
-
-@node Lists
-@section Lists and Sexps
-
-@cindex Control-Meta
- By convention, Emacs keys for dealing with balanced expressions are
-usually Control-Meta characters. They tend to be analogous in function
-to their Control and Meta equivalents. (For example, @kbd{C-M-b} moves
-back over one balanced expression, which is analogous to @kbd{C-b} that
-moves one character back and to @kbd{M-b} which moves one word back.)
-These commands are usually thought of as pertaining to expressions in
-programming languages, but can be useful with any language in which some
-sort of parentheses exist (including human languages).
-
-@cindex list
-@cindex sexp
-@cindex expression
- These commands fall into two classes. Some deal only with @dfn{lists}
-(parenthetical groupings). They see nothing except parentheses, brackets,
-braces (whichever ones must balance in the language you are working with),
-and escape characters that might be used to quote those.
-
- The other commands deal with expressions or @dfn{sexps}. The word ``sexp''
-is derived from @dfn{s-expression}, the ancient term for an expression in
-Lisp. But in Emacs, the notion of ``sexp'' is not limited to Lisp. It
-refers to an expression in whatever language your program is written in.
-Each programming language has its own major mode, which customizes the
-syntax tables so that expressions in that language count as sexps.
-
- Sexps typically include symbols, numbers, and string constants, as well
-as anything contained in parentheses, brackets or braces.
-
- In languages that use prefix and infix operators, such as C, it is not
-possible for all expressions to be sexps. For example, C mode does not
-recognize @samp{foo + bar} as a sexp, even though it @emph{is} a C expression;
-it recognizes @samp{foo} as one sexp and @samp{bar} as another, with the
-@samp{+} as punctuation between them. This is a fundamental ambiguity:
-both @samp{foo + bar} and @samp{foo} are legitimate choices for the sexp to
-move over if point is at the @samp{f}. Note that @samp{(foo + bar)} is a
-single sexp in C mode.
-
- Some languages have obscure forms of expression syntax that nobody
-has bothered to make Emacs understand properly.
-
-@node List Commands
-@section List And Sexp Commands
-
-@c doublewidecommands
-@table @kbd
-@item C-M-f
-Move forward over a sexp (@code{forward-sexp}).
-@item C-M-b
-Move backward over a sexp (@code{backward-sexp}).
-@item C-M-k
-Kill sexp forward (@code{kill-sexp}).
-@item C-M-@key{DEL}
-Kill sexp backward (@code{backward-kill-sexp}).
-@item C-M-u
-Move up and backward in list structure (@code{backward-up-list}).
-@item C-M-d
-Move down and forward in list structure (@code{down-list}).
-@item C-M-n
-Move forward over a list (@code{forward-list}).
-@item C-M-p
-Move backward over a list (@code{backward-list}).
-@item C-M-t
-Transpose expressions (@code{transpose-sexps}).
-@item C-M-@@
-Put mark after following expression (@code{mark-sexp}).
-@end table
-
-@cindex parentheses, moving across
-@cindex matching parenthesis and braces, moving to
-@cindex braces, moving across
-@kindex C-M-f
-@kindex C-M-b
-@findex forward-sexp
-@findex backward-sexp
- To move forward over a sexp, use @kbd{C-M-f} (@code{forward-sexp}). If
-the first significant character after point is an opening delimiter
-(@samp{(} in Lisp; @samp{(}, @samp{[} or @samp{@{} in C), @kbd{C-M-f}
-moves past the matching closing delimiter. If the character begins a
-symbol, string, or number, @kbd{C-M-f} moves over that.
+ Turning on a major mode runs a normal hook called the @dfn{mode
+hook}, which is the value of a Lisp variable. Each major mode has a
+mode hook, and the hook's name is always made from the mode command's
+name by adding @samp{-hook}. For example, turning on C mode runs the
+hook @code{c-mode-hook}, while turning on Lisp mode runs the hook
+@code{lisp-mode-hook}. The purpose of the mode hook is to give you a
+place to set up customizations for that major mode. @xref{Hooks}.
- The command @kbd{C-M-b} (@code{backward-sexp}) moves backward over a
-sexp. The detailed rules are like those above for @kbd{C-M-f}, but with
-directions reversed. If there are any prefix characters (single-quote,
-backquote and comma, in Lisp) preceding the sexp, @kbd{C-M-b} moves back
-over them as well. The sexp commands move across comments as if they
-were whitespace in most modes.
+@node Defuns
+@section Top-Level Definitions, or Defuns
- @kbd{C-M-f} or @kbd{C-M-b} with an argument repeats that operation the
-specified number of times; with a negative argument, it moves in the
-opposite direction.
+ In Emacs, a major definition at the top level in the buffer,
+something like a function, is called a @dfn{defun}. The name comes
+from Lisp, but in Emacs we use it for all languages.
-@cindex deleting parenthesized expressions
-@kindex C-M-k
-@findex kill-sexp
-@kindex C-M-DEL
-@findex backward-kill-sexp
- Killing a whole sexp can be done with @kbd{C-M-k} (@code{kill-sexp})
-or @kbd{C-M-@key{DEL}} (@code{backward-kill-sexp}). @kbd{C-M-k} kills
-the characters that @kbd{C-M-f} would move over, and @kbd{C-M-@key{DEL}}
-kills the characters that @kbd{C-M-b} would move over.
+@menu
+* Left Margin Paren:: An open-paren or similar opening delimiter
+ starts a defun if it is at the left margin.
+* Moving by Defuns:: Commands to move over or mark a major definition.
+* Imenu:: Making buffer indexes as menus.
+* Which Function:: Which Function mode shows which function you are in.
+@end menu
-@kindex C-M-n
-@kindex C-M-p
-@findex forward-list
-@findex backward-list
- The @dfn{list commands} move over lists, as the sexp commands do, but skip
-blithely over any number of other kinds of sexps (symbols, strings, etc.).
-They are @kbd{C-M-n} (@code{forward-list}) and @kbd{C-M-p}
-(@code{backward-list}). The main reason they are useful is that they
-usually ignore comments (since the comments usually do not contain any
-lists).@refill
+@node Left Margin Paren
+@subsection Left Margin Convention
-@kindex C-M-u
-@kindex C-M-d
-@findex backward-up-list
-@findex down-list
- @kbd{C-M-n} and @kbd{C-M-p} stay at the same level in parentheses, when
-that's possible. To move @emph{up} one (or @var{n}) levels, use @kbd{C-M-u}
-(@code{backward-up-list}).
-@kbd{C-M-u} moves backward up past one unmatched opening delimiter. A
-positive argument serves as a repeat count; a negative argument reverses
-direction of motion and also requests repetition, so it moves forward and
-up one or more levels.@refill
-
- To move @emph{down} in list structure, use @kbd{C-M-d}
-(@code{down-list}). In Lisp mode, where @samp{(} is the only opening
-delimiter, this is nearly the same as searching for a @samp{(}. An
-argument specifies the number of levels of parentheses to go down.
+@cindex open-parenthesis in leftmost column
+@cindex ( in leftmost column
+ Emacs assumes by default that any opening delimiter found at the
+left margin is the start of a top-level definition, or defun. You can
+override this default by setting this user option:
+
+@defvar open-paren-in-column-0-is-defun-start
+If this user option is set to @code{t} (the default), opening
+parentheses or braces at column zero always start defuns. When it's
+@code{nil}, defuns are found by searching for parens or braces at the
+outermost level. Some major modes, including C and related modes, set
+@code{open-paren-in-column-0-is-defun-start} buffer-locally to
+@code{nil}
+@end defvar
+
+ In modes where @code{open-paren-in-column-0-is-defun-start} is
+@code{t}, @strong{don't put an opening delimiter at the left margin
+unless it is a defun start}. For instance, never put an
+open-parenthesis at the left margin in a Lisp file unless it is the
+start of a top-level list.
-@cindex transposition of parenthesized expressions
-@kindex C-M-t
-@findex transpose-sexps
- A somewhat random-sounding command which is nevertheless handy is
-@kbd{C-M-t} (@code{transpose-sexps}), which drags the previous sexp
-across the next one. An argument serves as a repeat count, and a
-negative argument drags backwards (thus canceling out the effect of
-@kbd{C-M-t} with a positive argument). An argument of zero, rather than
-doing nothing, transposes the sexps ending after point and the mark.
+ If you don't follow this convention, not only will you have trouble
+when you explicitly use the commands for motion by defuns; other
+features that use them will also give you trouble. This includes
+the indentation commands (@pxref{Program Indent}) and Font Lock
+mode (@pxref{Font Lock}).
-@kindex C-M-@@
-@findex mark-sexp
- To set the region around the next sexp in the buffer, use @kbd{C-M-@@}
-(@code{mark-sexp}), which sets mark at the same place that @kbd{C-M-f}
-would move to. @kbd{C-M-@@} takes arguments like @kbd{C-M-f}. In
-particular, a negative argument is useful for putting the mark at the
-beginning of the previous sexp.
+ The most likely problem case is when you want an opening delimiter
+at the start of a line inside a string. To avoid trouble, put an
+escape character (@samp{\}, in Emacs Lisp, @samp{/} in some other Lisp
+dialects) before the opening delimiter. This will not affect the
+contents of the string, but will prevent that opening delimiter from
+starting a defun. Here's an example:
- The list and sexp commands' understanding of syntax is completely
-controlled by the syntax table. Any character can, for example, be
-declared to be an opening delimiter and act like an open parenthesis.
-@xref{Syntax}.
+@example
+ (insert "Foo:
+\(bar)
+")
+@end example
-@node Defuns
-@section Defuns
+ To help you catch violations of this convention, Font Lock mode
+highlights confusing opening delimiters (those that ought to be
+quoted) in bold red.
+
+ In the earliest days, the original Emacs found defuns by moving
+upward a level of parentheses or braces until there were no more
+levels to go up. This always required scanning all the way back to
+the beginning of the buffer, even for a small function. To speed up
+the operation, we changed Emacs to assume that any opening delimiter
+at the left margin is the start of a defun. This heuristic is nearly
+always right, and avoids the need to scan back to the beginning of the
+buffer. However, now that modern computers are so powerful, this
+scanning is rarely slow enough to annoy, so we've provided a way to
+disable the heuristic.
+
+@node Moving by Defuns
+@subsection Moving by Defuns
@cindex defuns
- In Emacs, a parenthetical grouping at the top level in the buffer is
-called a @dfn{defun}. The name derives from the fact that most top-level
-lists in a Lisp file are instances of the special form @code{defun}, but
-any top-level parenthetical grouping counts as a defun in Emacs parlance
-regardless of what its contents are, and regardless of the programming
-language in use. For example, in C, the body of a function definition is a
-defun.
-
+ These commands move point or set up the region based on top-level
+major definitions, also called @dfn{defuns}.
-@cindex move to beginning or end of function
-@cindex function, move to beginning or end
-@kindex C-M-a
-@kindex C-M-e
-@kindex C-M-h
-@findex beginning-of-defun
-@findex end-of-defun
-@findex mark-defun
-@c doublewidecommands
@table @kbd
@item C-M-a
Move to beginning of current or preceding defun
Put region around whole current or following defun (@code{mark-defun}).
@end table
+@cindex move to beginning or end of function
+@cindex function, move to beginning or end
+@kindex C-M-a
+@kindex C-M-e
+@kindex C-M-h
+@findex beginning-of-defun
+@findex end-of-defun
+@findex mark-defun
+ The commands to move to the beginning and end of the current defun
+are @kbd{C-M-a} (@code{beginning-of-defun}) and @kbd{C-M-e}
+(@code{end-of-defun}). If you repeat one of these commands, or use a
+positive numeric argument, each repetition moves to the next defun in
+the direction of motion.
+
+ @kbd{C-M-a} with a negative argument @minus{}@var{n} moves forward
+@var{n} times to the next beginning of a defun. This is not exactly
+the same place that @kbd{C-M-e} with argument @var{n} would move to;
+the end of this defun is not usually exactly the same place as the
+beginning of the following defun. (Whitespace, comments, and perhaps
+declarations can separate them.) Likewise, @kbd{C-M-e} with a
+negative argument moves back to an end of a defun, which is not quite
+the same as @kbd{C-M-a} with a positive argument.
+
@kindex C-M-h @r{(C mode)}
@findex c-mark-function
- If you wish to operate on the current defun, use @kbd{C-M-h}
-(@code{mark-defun}) which puts point at the beginning and mark at the end
-of the current or next defun. For example, this is the easiest way to get
-ready to move the defun to a different place in the text. In C mode,
-@kbd{C-M-h} runs the function @code{c-mark-function}, which is almost the
-same as @code{mark-defun}; the difference is that it backs up over the
-argument declarations, function name and returned data type so that the
-entire C function is inside the region. @xref{Marking Objects}.
+ To operate on the current defun, use @kbd{C-M-h} (@code{mark-defun})
+which puts point at the beginning and mark at the end of the current
+defun. This is the easiest way to get ready to kill the defun in
+order to move it to a different place in the file. If you use the
+command while point is between defuns, it uses the following defun.
+Successive uses of @kbd{C-M-h}, or using it in Transient Mark mode
+when the mark is active, extends the end of the region to include one
+more defun each time.
+
+ In C mode, @kbd{C-M-h} runs the function @code{c-mark-function},
+which is almost the same as @code{mark-defun}; the difference is that
+it backs up over the argument declarations, function name and returned
+data type so that the entire C function is inside the region. This is
+an example of how major modes adjust the standard key bindings so that
+they do their standard jobs in a way better fitting a particular
+language. Other major modes may replace any or all of these key
+bindings for that purpose.
-@cindex open-parenthesis in leftmost column
-@cindex ( in leftmost column
- Emacs assumes that any open-parenthesis found in the leftmost column
-is the start of a defun. Therefore, @strong{never put an
-open-parenthesis at the left margin in a Lisp file unless it is the
-start of a top-level list. Never put an open-brace or other opening
-delimiter at the beginning of a line of C code unless it starts the body
-of a function.} The most likely problem case is when you want an
-opening delimiter at the start of a line inside a string. To avoid
-trouble, put an escape character (@samp{\}, in C and Emacs Lisp,
-@samp{/} in some other Lisp dialects) before the opening delimiter. It
-will not affect the contents of the string.
-
- In the remotest past, the original Emacs found defuns by moving upward a
-level of parentheses until there were no more levels to go up. This always
-required scanning all the way back to the beginning of the buffer, even for
-a small function. To speed up the operation, Emacs was changed to assume
-that any @samp{(} (or other character assigned the syntactic class of
-opening-delimiter) at the left margin is the start of a defun. This
-heuristic is nearly always right and avoids the costly scan; however,
-it mandates the convention described above.
+@node Imenu
+@subsection Imenu
+@cindex index of buffer definitions
+@cindex buffer definitions index
+@cindex tags
+
+ The Imenu facility offers a way to find the major definitions in
+a file by name. It is also useful in text formatter major modes,
+where it treats each chapter, section, etc., as a definition.
+(@xref{Tags}, for a more powerful feature that handles multiple files
+together.)
+
+@findex imenu
+ If you type @kbd{M-x imenu}, it reads the name of a definition using
+the minibuffer, then moves point to that definition. You can use
+completion to specify the name; the command always displays the whole
+list of valid names.
+
+@findex imenu-add-menubar-index
+ Alternatively, you can bind the command @code{imenu} to a mouse
+click. Then it displays mouse menus for you to select a definition
+name. You can also add the buffer's index to the menu bar by calling
+@code{imenu-add-menubar-index}. If you want to have this menu bar
+item available for all buffers in a certain major mode, you can do
+this by adding @code{imenu-add-menubar-index} to its mode hook. But
+if you have done that, you will have to wait a little while each time
+you visit a file in that mode, while Emacs finds all the definitions
+in that buffer.
+
+@vindex imenu-auto-rescan
+ When you change the contents of a buffer, if you add or delete
+definitions, you can update the buffer's index based on the
+new contents by invoking the @samp{*Rescan*} item in the menu.
+Rescanning happens automatically if you set @code{imenu-auto-rescan} to
+a non-@code{nil} value. There is no need to rescan because of small
+changes in the text.
+
+@vindex imenu-sort-function
+ You can customize the way the menus are sorted by setting the
+variable @code{imenu-sort-function}. By default, names are ordered as
+they occur in the buffer; if you want alphabetic sorting, use the
+symbol @code{imenu--sort-by-name} as the value. You can also
+define your own comparison function by writing Lisp code.
+
+ Imenu provides the information to guide Which Function mode
+@ifnottex
+(@pxref{Which Function}).
+@end ifnottex
+@iftex
+(see below).
+@end iftex
+The Speedbar can also use it (@pxref{Speedbar}).
+
+@node Which Function
+@subsection Which Function Mode
+@cindex current function name in mode line
+
+ Which Function mode is a minor mode that displays the current
+function name in the mode line, updating it as you move around in a
+buffer.
+
+@findex which-function-mode
+@vindex which-func-modes
+ To enable (or disable) Which Function mode, use the command @kbd{M-x
+which-function-mode}. This command is global; it applies to all
+buffers, both existing ones and those yet to be created. However, it
+takes effect only in certain major modes, those listed in the value of
+@code{which-func-modes}. If the value is @code{t}, then Which Function
+mode applies to all major modes that know how to support it---in other
+words, all the major modes that support Imenu.
@node Program Indent
@section Indentation for Programs
* Custom C Indent:: Controlling indentation style for C and related modes.
@end menu
+@cindex pretty-printer
Emacs also provides a Lisp pretty-printer in the library @code{pp}.
This program reformats a Lisp object with indentation chosen to look nice.
@node Basic Indent
@subsection Basic Program Indentation Commands
-@c WideCommands
+ The basic indentation commands indent a single line according to the
+usual conventions of the language you are editing.
+
@table @kbd
@item @key{TAB}
Adjust indentation of current line.
@item C-j
-Equivalent to @key{RET} followed by @key{TAB} (@code{newline-and-indent}).
+Insert a newline, then adjust indentation of following line
+(@code{newline-and-indent}).
@end table
@kindex TAB @r{(programming modes)}
@findex c-indent-command
@findex indent-line-function
+@findex indent-for-tab-command
The basic indentation command is @key{TAB}, which gives the current line
the correct indentation as determined from the previous lines. The
-function that @key{TAB} runs depends on the major mode; it is @code{indent-for-tab-command}
+function that @key{TAB} runs depends on the major mode; it is
+@code{lisp-indent-line}
in Lisp mode, @code{c-indent-command} in C mode, etc. These functions
-understand different syntaxes for different languages, but they all do
-about the same thing. @key{TAB} in any programming-language major mode
+understand the syntax and conventions of different languages, but they all do
+conceptually the same job: @key{TAB} in any programming-language major mode
inserts or deletes whitespace at the beginning of the current line,
-independent of where point is in the line. If point is inside the
-whitespace at the beginning of the line, @key{TAB} leaves it at the end of
-that whitespace; otherwise, @key{TAB} leaves point fixed with respect to
+independent of where point is in the line. If point was inside the
+whitespace at the beginning of the line, @key{TAB} puts it at the end of
+that whitespace; otherwise, @key{TAB} keeps point fixed with respect to
the characters around it.
- Use @kbd{C-q @key{TAB}} to insert a tab at point.
+ Use @kbd{C-q @key{TAB}} to insert a tab character at point.
@kindex C-j
@findex newline-and-indent
- When entering lines of new code, use @kbd{C-j} (@code{newline-and-indent}),
-which is equivalent to a @key{RET} followed by a @key{TAB}. @kbd{C-j} creates
-a blank line and then gives it the appropriate indentation.
-
- @key{TAB} indents the second and following lines of the body of a
-parenthetical grouping each under the preceding one; therefore, if you
-alter one line's indentation to be nonstandard, the lines below will
-tend to follow it. This behavior is convenient in cases where you have
-overridden the standard result of @key{TAB} because you find it
-unaesthetic for a particular line.
-
- Remember that an open-parenthesis, open-brace or other opening delimiter
-at the left margin is assumed by Emacs (including the indentation routines)
-to be the start of a function. Therefore, you must never have an opening
-delimiter in column zero that is not the beginning of a function, not even
-inside a string. This restriction is vital for making the indentation
-commands fast; you must simply accept it. @xref{Defuns}, for more
-information on this.
+ When entering lines of new code, use @kbd{C-j}
+(@code{newline-and-indent}), which inserts a newline and then adjusts
+indentation after it. (It also deletes any trailing whitespace which
+remains before the new newline.) Thus, @kbd{C-j} at the end of a line
+creates a blank line with appropriate indentation. In programming
+language modes, it is equivalent to @key{RET} @key{TAB}.
+
+ @key{TAB} indents a line that starts within a parenthetical grouping
+under the preceding line within the grouping, or the text after the
+parenthesis. Therefore, if you manually give one of these lines a
+nonstandard indentation, the lines below will tend to follow it. This
+behavior is convenient in cases where you have overridden the standard
+result of @key{TAB} because you find it unaesthetic for a particular
+line.
+
+ In some modes, an open-parenthesis, open-brace or other opening
+delimiter at the left margin is assumed by Emacs (including the
+indentation routines) to be the start of a function. This speeds up
+indentation commands. If you will be editing text which contains
+opening delimiters in column zero that aren't the beginning of a
+functions, even inside strings or comments, you must set
+@code{open-paren-in-column-0-is-defun-start}. @xref{Left Margin
+Paren}, for more information on this.
Normally, lines are indented with tabs and spaces. If you want Emacs
-to use spaces only, see @ref{Just Spaces}.
+to use spaces only, set @code{indent-tabs-mode} (@pxref{Just Spaces}).
@node Multi-line Indent
@subsection Indenting Several Lines
- When you wish to reindent several lines of code which have been altered
-or moved to a different level in the list structure, you have several
-commands available.
+ When you wish to reindent several lines of code which have been
+altered or moved to a different level in the parenthesis structure,
+you have several commands available.
@table @kbd
@item C-M-q
-Reindent all the lines within one list (@code{indent-sexp}).
-@item C-u @key{TAB}
-Shift an entire list rigidly sideways so that its first line
-is properly indented.
+Reindent all the lines within one parenthetical grouping (@code{indent-pp-sexp}).
@item C-M-\
Reindent all lines in the region (@code{indent-region}).
+@item C-u @key{TAB}
+Shift an entire parenthetical grouping rigidly sideways so that its
+first line is properly indented.
+@item M-x indent-code-rigidly
+Shift all the lines in the region rigidly sideways, but do not alter
+lines that start inside comments and strings.
@end table
@kindex C-M-q
-@findex indent-sexp
- You can reindent the contents of a single list by positioning point
-before the beginning of it and typing @kbd{C-M-q} (@code{indent-sexp} in
-Lisp mode, @code{c-indent-exp} in C mode; also bound to other suitable
-commands in other modes). The indentation of the line the sexp starts on
-is not changed; therefore, only the relative indentation within the list,
-and not its position, is changed. To correct the position as well, type a
-@key{TAB} before the @kbd{C-M-q}.
+@findex indent-pp-sexp
+ You can reindent the contents of a single parenthetical grouping by
+positioning point before the beginning of it and typing @kbd{C-M-q}
+(@code{indent-pp-sexp} in Lisp mode, @code{c-indent-exp} in C mode; also
+bound to other suitable commands in other modes). The indentation of
+the line where the grouping starts is not changed; therefore this
+changes only the relative indentation within the grouping, not its
+overall indentation. To correct that as well, type @key{TAB} first.
+
+ Another way to specify the range to be reindented is with the
+region. The command @kbd{C-M-\} (@code{indent-region}) applies
+@key{TAB} to every line whose first character is between point and
+mark.
@kindex C-u TAB
- If the relative indentation within a list is correct but the
-indentation of its first line is not, go to that line and type @kbd{C-u
-@key{TAB}}. @key{TAB} with a numeric argument reindents the current
-line as usual, then reindents by the same amount all the lines in the
-grouping starting on the current line. In other words, it reindents the
-whole grouping rigidly as a unit. It is clever, though, and does not
-alter lines that start inside strings, or C preprocessor lines when in C
-mode.
-
- Another way to specify the range to be reindented is with the region.
-The command @kbd{C-M-\} (@code{indent-region}) applies @key{TAB} to
-every line whose first character is between point and mark.
+ If you like the relative indentation within a grouping, but not the
+indentation of its first line, you can type @kbd{C-u @key{TAB}} to
+reindent the whole grouping as a rigid unit. (This works in Lisp
+modes and C and related modes.) @key{TAB} with a numeric argument
+reindents the current line as usual, then reindents by the same amount
+all the lines in the parenthetical grouping starting on the current
+line. It is clever, though, and does not alter lines that start
+inside strings. Neither does it alter C preprocessor lines when in C
+mode, but it does reindent any continuation lines that may be attached
+to them.
+
+@findex indent-code-rigidly
+ You can also perform this operation on the region, using the command
+@kbd{M-x indent-code-rigidly}. It rigidly shifts all the lines in the
+region sideways, like @code{indent-rigidly} does (@pxref{Indentation
+Commands}). It doesn't alter the indentation of lines that start
+inside a string, unless the region also starts inside that string.
+The prefix arg specifies the number of columns to indent.
@node Lisp Indent
@subsection Customizing Lisp Indentation
the containing list.
@vindex lisp-body-indent
- The standard pattern is overridden for certain functions. Functions
-whose names start with @code{def} always indent the second line by
-@code{lisp-body-indent} extra columns beyond the open-parenthesis
-starting the expression.
-
- The standard pattern can be overridden in various ways for individual
-functions, according to the @code{lisp-indent-function} property of the
-function name. There are four possibilities for this property:
-
-@table @asis
-@item @code{nil}
-This is the same as no property; the standard indentation pattern is used.
-@item @code{defun}
-The pattern used for function names that start with @code{def} is used for
-this function also.
-@item a number, @var{number}
-The first @var{number} arguments of the function are
-@dfn{distinguished} arguments; the rest are considered the @dfn{body}
-of the expression. A line in the expression is indented according to
-whether the first argument on it is distinguished or not. If the
-argument is part of the body, the line is indented @code{lisp-body-indent}
-more columns than the open-parenthesis starting the containing
-expression. If the argument is distinguished and is either the first
-or second argument, it is indented @emph{twice} that many extra columns.
-If the argument is distinguished and not the first or second argument,
-the standard pattern is followed for that line.
-@item a symbol, @var{symbol}
-@var{symbol} should be a function name; that function is called to
-calculate the indentation of a line within this expression. The
-function receives two arguments:
-@table @asis
-@item @var{state}
-The value returned by @code{parse-partial-sexp} (a Lisp primitive for
-indentation and nesting computation) when it parses up to the
-beginning of this line.
-@item @var{pos}
-The position at which the line being indented begins.
-@end table
-@noindent
-It should return either a number, which is the number of columns of
-indentation for that line, or a list whose car is such a number. The
-difference between returning a number and returning a list is that a
-number says that all following lines at the same nesting level should
-be indented just like this one; a list says that following lines might
-call for different indentations. This makes a difference when the
-indentation is being computed by @kbd{C-M-q}; if the value is a
-number, @kbd{C-M-q} need not recalculate indentation for the following
-lines until the end of the list.
-@end table
+ Certain functions override the standard pattern. Functions whose
+names start with @code{def} treat the second lines as the start of
+a @dfn{body}, by indenting the second line @code{lisp-body-indent}
+additional columns beyond the open-parenthesis that starts the
+expression.
+
+@cindex @code{lisp-indent-function} property
+ You can override the standard pattern in various ways for individual
+functions, according to the @code{lisp-indent-function} property of
+the function name. Normally you would use this for macro definitions
+and specify it using the @code{declare} construct (@pxref{Defining
+Macros,,, elisp, the Emacs Lisp Reference Manual}).
@node C Indent
@subsection Commands for C Indentation
- Here are the commands for indentation in C mode and related modes:
+ Here are special features for indentation in C mode and related modes:
@table @code
@item C-c C-q
@kindex C-M-q @r{(C mode)}
@findex c-indent-exp
Reindent each line in the balanced expression that follows point
-(@code{c-indent-exp}). A prefix argument inhibits error checking and
-warning messages about invalid syntax.
+(@code{c-indent-exp}). A prefix argument inhibits warning messages
+about invalid syntax.
@item @key{TAB}
@findex c-indent-command
Reindent the current line, and/or in some cases insert a tab character
(@code{c-indent-command}).
+@vindex c-tab-always-indent
If @code{c-tab-always-indent} is @code{t}, this command always reindents
the current line and does nothing else. This is the default.
if @code{indent-tabs-mode} is @code{nil}).
Any other value (not @code{nil} or @code{t}) means always reindent the
-line, and also insert a tab if within a comment, a string, or a
-preprocessor directive.
-
-@item C-u @key{TAB}
-Reindent the current line according to its syntax; also rigidly reindent
-any other lines of the expression that starts on the current line.
-@xref{Multi-line Indent}.
+line, and also insert a tab if within a comment or a string.
@end table
To reindent the whole current buffer, type @kbd{C-x h C-M-\}. This
@node Custom C Indent
@subsection Customizing C Indentation
+@cindex style (for indentation)
- C mode and related modes use a simple yet flexible mechanism for
-customizing indentation. The mechanism works in two steps: first it
-classifies the line syntactically according to its contents and context;
-second, it associates each kind of syntactic construct with an
-indentation offset which you can customize.
-
-@menu
-* Syntactic Analysis::
-* Indentation Calculation::
-* Changing Indent Style::
-* Syntactic Symbols::
-* Variables for C Indent::
-* C Indent Styles::
-@end menu
-
-@node Syntactic Analysis
-@subsubsection Step 1---Syntactic Analysis
-@cindex syntactic analysis
-
- In the first step, the C indentation mechanism looks at the line
-before the one you are currently indenting and determines the syntactic
-components of the construct on that line. It builds a list of these
-syntactic components, each of which contains a @dfn{syntactic symbol}
-and sometimes also a buffer position. Some syntactic symbols describe
-grammatical elements, for example @code{statement} and
-@code{substatement}; others describe locations amidst grammatical
-elements, for example @code{class-open} and @code{knr-argdecl}.
-
- Conceptually, a line of C code is always indented relative to the
-indentation of some line higher up in the buffer. This is represented
-by the buffer positions in the syntactic component list.
-
- Here is an example. Suppose we have the following code in a C++ mode
-buffer (the line numbers don't actually appear in the buffer):
+ C mode and related modes use a flexible mechanism for customizing
+indentation. C mode indents a source line in two steps: first it
+classifies the line syntactically according to its contents and
+context; second, it determines the indentation offset associated by
+your selected @dfn{style} with the syntactic construct and adds this
+onto the indentation of the @dfn{anchor statement}.
-@example
-1: void swap (int& a, int& b)
-2: @{
-3: int tmp = a;
-4: a = b;
-5: b = tmp;
-6: @}
-@end example
-
- If you type @kbd{C-c C-s} (which runs the command
-@code{c-show-syntactic-information}) on line 4, it shows the result of
-the indentation mechanism for that line:
+@table @kbd
+@item C-c . @key{RET} @var{style} @key{RET}
+Select a predefined style @var{style} (@code{c-set-style}).
+@end table
-@example
-syntactic analysis: ((statement . 32))
-@end example
+ A @dfn{style} is a named collection of customizations that can be
+used in C mode and the related modes. @ref{Styles,,, ccmode, The CC
+Mode Manual}, for a complete description. Emacs comes with several
+predefined styles, including @code{gnu}, @code{k&r}, @code{bsd},
+@code{stroustrup}, @code{linux}, @code{python}, @code{java},
+@code{whitesmith}, @code{ellemtel}, and @code{awk}. Some of these
+styles are primarily intended for one language, but any of them can be
+used with any of the languages supported by these modes. To find out
+what a style looks like, select it and reindent some code, e.g., by
+typing @key{C-M-q} at the start of a function definition.
+
+@kindex C-c . @r{(C mode)}
+@findex c-set-style
+ To choose a style for the current buffer, use the command @w{@kbd{C-c
+.}}. Specify a style name as an argument (case is not significant).
+This command affects the current buffer only, and it affects only
+future invocations of the indentation commands; it does not reindent
+the code already in the buffer. To reindent the whole buffer in the
+new style, you can type @kbd{C-x h C-M-\}.
- This indicates that the line is a statement and it is indented
-relative to buffer position 32, which happens to be the @samp{i} in
-@code{int} on line 3. If you move the cursor to line 3 and type
-@kbd{C-c C-s}, it displays this:
+@vindex c-default-style
+ You can also set the variable @code{c-default-style} to specify the
+default style for various major modes. Its value should be either the
+style's name (a string) or an alist, in which each element specifies
+one major mode and which indentation style to use for it. For
+example,
@example
-syntactic analysis: ((defun-block-intro . 28))
+(setq c-default-style
+ '((java-mode . "java") (awk-mode . "awk") (other . "gnu")))
@end example
- This indicates that the @code{int} line is the first statement in a
-block, and is indented relative to buffer position 28, which is the
-brace just after the function header.
-
@noindent
-Here is another example:
-
-@example
-1: int add (int val, int incr, int doit)
-2: @{
-3: if (doit)
-4: @{
-5: return (val + incr);
-6: @}
-7: return (val);
-8: @}
-@end example
+specifies explicit choices for Java and AWK modes, and the default
+@samp{gnu} style for the other C-like modes. (These settings are
+actually the defaults.) This variable takes effect when you select
+one of the C-like major modes; thus, if you specify a new default
+style for Java mode, you can make it take effect in an existing Java
+mode buffer by typing @kbd{M-x java-mode} there.
+
+ The @code{gnu} style specifies the formatting recommended by the GNU
+Project for C; it is the default, so as to encourage use of our
+recommended style.
+
+ @xref{Indentation Engine Basics,,, ccmode, the CC Mode Manual}, and
+@ref{Customizing Indentation,,, ccmode, the CC Mode Manual}, for more
+information on customizing indentation for C and related modes,
+including how to override parts of an existing style and how to define
+your own styles.
+
+@node Parentheses
+@section Commands for Editing with Parentheses
-@noindent
-Typing @kbd{C-c C-s} on line 4 displays this:
+@findex check-parens
+@cindex unbalanced parentheses and quotes
+ This section describes the commands and features that take advantage
+of the parenthesis structure in a program, or help you keep it
+balanced.
-@example
-syntactic analysis: ((substatement-open . 43))
-@end example
+ When talking about these facilities, the term ``parenthesis'' also
+includes braces, brackets, or whatever delimiters are defined to match
+in pairs. The major mode controls which delimiters are significant,
+through the syntax table (@pxref{Syntax}). In Lisp, only parentheses
+count; in C, these commands apply to braces and brackets too.
- This says that the brace @emph{opens} a substatement block. By the
-way, a @dfn{substatement} indicates the line after an @code{if},
-@code{else}, @code{while}, @code{do}, @code{switch}, @code{for},
-@code{try}, @code{catch}, @code{finally}, or @code{synchronized}
-statement.
-
-@cindex syntactic component
-@cindex syntactic symbol
-@vindex c-syntactic-context
- Within the C indentation commands, after a line has been analyzed
-syntactically for indentation, the variable @code{c-syntactic-context}
-contains a list that describes the results. Each element in this list
-is a @dfn{syntactic component}: a cons cell containing a syntactic
-symbol and (optionally) its corresponding buffer position. There may be
-several elements in a component list; typically only one element has a
-buffer position.
-
-@node Indentation Calculation
-@subsubsection Step 2---Indentation Calculation
-@cindex Indentation Calculation
-
- The C indentation mechanism calculates the indentation for the current
-line using the list of syntactic components, @code{c-syntactic-context},
-derived from syntactic analysis. Each component is a cons cell that
-contains a syntactic symbol and may also contain a buffer position.
-
- Each component contributes to the final total indentation of the line
-in two ways. First, the syntactic symbol identifies an element of
-@code{c-offsets-alist}, which is an association list mapping syntactic
-symbols into indentation offsets. Each syntactic symbol's offset adds
-to the total indentation. Second, if the component includes a buffer
-position, the column number of that position adds to the indentation.
-All these offsets and column numbers, added together, give the total
-indentation.
-
- The following examples demonstrate the workings of the C indentation
-mechanism:
+ You can use @kbd{M-x check-parens} to find any unbalanced
+parentheses and unbalanced string quotes in the buffer.
-@example
-1: void swap (int& a, int& b)
-2: @{
-3: int tmp = a;
-4: a = b;
-5: b = tmp;
-6: @}
-@end example
+@menu
+* Expressions:: Expressions with balanced parentheses.
+* Moving by Parens:: Commands for moving up, down and across
+ in the structure of parentheses.
+* Matching:: Insertion of a close-delimiter flashes matching open.
+@end menu
- Suppose that point is on line 3 and you type @key{TAB} to reindent the
-line. As explained above (@pxref{Syntactic Analysis}), the syntactic
-component list for that line is:
+@node Expressions
+@subsection Expressions with Balanced Parentheses
-@example
-((defun-block-intro . 28))
-@end example
+@cindex sexp
+@cindex expression
+@cindex balanced expression
+ These commands deal with balanced expressions, also called
+@dfn{sexps}@footnote{The word ``sexp'' is used to refer to an
+expression in Lisp.}.
- In this case, the indentation calculation first looks up
-@code{defun-block-intro} in the @code{c-offsets-alist} alist. Suppose
-that it finds the integer 2; it adds this to the running total
-(initialized to zero), yielding a updated total indentation of 2 spaces.
+@table @kbd
+@item C-M-f
+Move forward over a balanced expression (@code{forward-sexp}).
+@item C-M-b
+Move backward over a balanced expression (@code{backward-sexp}).
+@item C-M-k
+Kill balanced expression forward (@code{kill-sexp}).
+@item C-M-t
+Transpose expressions (@code{transpose-sexps}).
+@item C-M-@@
+@itemx C-M-@key{SPC}
+Put mark after following expression (@code{mark-sexp}).
+@end table
- The next step is to find the column number of buffer position 28.
-Since the brace at buffer position 28 is in column zero, this adds 0 to
-the running total. Since this line has only one syntactic component,
-the total indentation for the line is 2 spaces.
+ Each programming language major mode customizes the definition of
+balanced expressions to suit that language. Balanced expressions
+typically include symbols, numbers, and string constants, as well as
+any pair of matching delimiters and their contents. Some languages
+have obscure forms of expression syntax that nobody has bothered to
+implement in Emacs.
-@example
-1: int add (int val, int incr, int doit)
-2: @{
-3: if (doit)
-4: @{
-5: return(val + incr);
-6: @}
-7: return(val);
-8: @}
-@end example
+@cindex Control-Meta
+ By convention, the keys for these commands are all Control-Meta
+characters. They usually act on expressions just as the corresponding
+Meta characters act on words. For instance, the command @kbd{C-M-b}
+moves backward over a balanced expression, just as @kbd{M-b} moves
+back over a word.
- If you type @key{TAB} on line 4, the same process is performed, but
-with different data. The syntactic component list for this line is:
+@kindex C-M-f
+@kindex C-M-b
+@findex forward-sexp
+@findex backward-sexp
+ To move forward over a balanced expression, use @kbd{C-M-f}
+(@code{forward-sexp}). If the first significant character after point
+is an opening delimiter (@samp{(} in Lisp; @samp{(}, @samp{[} or
+@samp{@{} in C), @kbd{C-M-f} moves past the matching closing
+delimiter. If the character begins a symbol, string, or number,
+@kbd{C-M-f} moves over that.
-@example
-((substatement-open . 43))
-@end example
+ The command @kbd{C-M-b} (@code{backward-sexp}) moves backward over a
+balanced expression. The detailed rules are like those above for
+@kbd{C-M-f}, but with directions reversed. If there are prefix
+characters (single-quote, backquote and comma, in Lisp) preceding the
+expression, @kbd{C-M-b} moves back over them as well. The balanced
+expression commands move across comments as if they were whitespace,
+in most modes.
- Here, the indentation calculation's first job is to look up the
-symbol @code{substatement-open} in @code{c-offsets-alist}. Let's assume
-that the offset for this symbol is 2. At this point the running total
-is 2 (0 + 2 = 2). Then it adds the column number of buffer position 43,
-which is the @samp{i} in @code{if} on line 3. This character is in
-column 2 on that line. Adding this yields a total indentation of 4
-spaces.
+ @kbd{C-M-f} or @kbd{C-M-b} with an argument repeats that operation the
+specified number of times; with a negative argument, it moves in the
+opposite direction.
-@vindex c-strict-syntax-p
- If a syntactic symbol in the analysis of a line does not appear in
-@code{c-offsets-alist}, it is ignored.
+@cindex killing expressions
+@kindex C-M-k
+@findex kill-sexp
+ Killing a whole balanced expression can be done with @kbd{C-M-k}
+(@code{kill-sexp}). @kbd{C-M-k} kills the characters that @kbd{C-M-f}
+would move over.
-@node Changing Indent Style
-@subsubsection Changing Indentation Style
+@cindex transposition of expressions
+@kindex C-M-t
+@findex transpose-sexps
+ A somewhat random-sounding command which is nevertheless handy is
+@kbd{C-M-t} (@code{transpose-sexps}), which drags the previous
+balanced expression across the next one. An argument serves as a
+repeat count, moving the previous expression over that many following
+ones. A negative argument drags the previous balanced expression
+backwards across those before it (thus canceling out the effect of
+@kbd{C-M-t} with a positive argument). An argument of zero, rather
+than doing nothing, transposes the balanced expressions ending at or
+after point and the mark.
- There are two ways to customize the indentation style for the C-like
-modes. First, you can select one of several predefined styles, each of
-which specifies offsets for all the syntactic symbols. For more
-flexibility, you can customize the handling of individual syntactic
-symbols. @xref{Syntactic Symbols}, for a list of all defined syntactic
-symbols.
+@kindex C-M-@@
+@kindex C-M-@key{SPC}
+@findex mark-sexp
+ To set the region around the next balanced expression in the buffer,
+use @kbd{C-M-@@} (@code{mark-sexp}), which sets mark at the same place
+that @kbd{C-M-f} would move to. @kbd{C-M-@@} takes arguments like
+@kbd{C-M-f}. In particular, a negative argument is useful for putting
+the mark at the beginning of the previous balanced expression. The
+alias @kbd{C-M-@key{SPC}} is equivalent to @kbd{C-M-@@}. When you
+repeat this command, or use it in Transient Mark mode when the mark is
+active, it extends the end of the region by one sexp each time.
+
+ In languages that use infix operators, such as C, it is not possible
+to recognize all balanced expressions as such because there can be
+multiple possibilities at a given position. For example, C mode does
+not treat @samp{foo + bar} as a single expression, even though it
+@emph{is} one C expression; instead, it recognizes @samp{foo} as one
+expression and @samp{bar} as another, with the @samp{+} as punctuation
+between them. Both @samp{foo + bar} and @samp{foo} are legitimate
+choices for ``the expression following point'' when point is at the
+@samp{f}, so the expression commands must perforce choose one or the
+other to operate on. Note that @samp{(foo + bar)} is recognized as a
+single expression in C mode, because of the parentheses.
+
+@node Moving by Parens
+@subsection Moving in the Parenthesis Structure
+
+@cindex parenthetical groupings
+@cindex parentheses, moving across
+@cindex matching parenthesis and braces, moving to
+@cindex braces, moving across
+@cindex list commands
+ The Emacs commands for handling parenthetical groupings see nothing
+except parentheses (or whatever characters must balance in the
+language you are working with), and the escape characters that might
+be used to quote those. They are mainly intended for editing
+programs, but can be useful for editing any text that has parentheses.
+They are sometimes called ``list'' commands because in Lisp these
+groupings are lists.
@table @kbd
-@item M-x c-set-style @key{RET} @var{style} @key{RET}
-Select predefined indentation style @var{style}. Type @kbd{?} when
-entering @var{style} to see a list of supported styles; to find out what
-a style looks like, select it and reindent some C code.
-
-@item C-c C-o @var{symbol} @key{RET} @var{offset} @key{RET}
-Set the indentation offset for syntactic symbol @var{symbol}
-(@code{c-set-offset}). The second argument @var{offset} specifies the
-new indentation offset.
+@item C-M-n
+Move forward over a parenthetical group (@code{forward-list}).
+@item C-M-p
+Move backward over a parenthetical group (@code{backward-list}).
+@item C-M-u
+Move up in parenthesis structure (@code{backward-up-list}).
+@item C-M-d
+Move down in parenthesis structure (@code{down-list}).
@end table
- The @code{c-offsets-alist} variable controls the amount of
-indentation to give to each syntactic symbol. Its value is an
-association list, and each element of the list has the form
-@code{(@var{syntactic-symbol} . @var{offset})}. By changing the offsets
-for various syntactic symbols, you can customize indentation in fine
-detail. To change this alist, use @code{c-set-offset} (see below).
-
- Each offset value in @code{c-offsets-alist} can be an integer, a
-function or variable name, a list, or one of the following symbols: @code{+},
-@code{-}, @code{++}, @code{--}, @code{*}, or @code{/}, indicating positive or negative
-multiples of the variable @code{c-basic-offset}. Thus, if you want to
-change the levels of indentation to be 3 spaces instead of 2 spaces, set
-@code{c-basic-offset} to 3.
-
- Using a function as the offset value provides the ultimate flexibility
-in customizing indentation. The function is called with a single
-argument containing the @code{cons} of the syntactic symbol and
-the buffer position, if any. The function should return an integer
-offset.
-
- If the offset value is a list, its elements are processed according
-to the rules above until a non-@code{nil} value is found. That value is
-then added to the total indentation in the normal manner. The primary
-use for this is to combine the results of several functions.
-
-@kindex C-c C-o @r{(C mode)}
-@findex c-set-offset
- The command @kbd{C-c C-o} (@code{c-set-offset}) is the easiest way to
-set offsets, both interactively or in your @file{~/.emacs} file. First
-specify the syntactic symbol, then the offset you want. @xref{Syntactic
-Symbols}, for a list of valid syntactic symbols and their meanings.
-
-@node Syntactic Symbols
-@subsubsection Syntactic Symbols
-
- Here is a table of valid syntactic symbols for indentation in C and
-related modes, with their syntactic meanings. Normally, most of these
-symbols are assigned offsets in @code{c-offsets-alist}.
-
-@table @code
-@item string
-Inside a multi-line string.
-
-@item c
-Inside a multi-line C style block comment.
-
-@item defun-open
-On a brace that opens a function definition.
+@kindex C-M-n
+@kindex C-M-p
+@findex forward-list
+@findex backward-list
+ The ``list'' commands @kbd{C-M-n} (@code{forward-list}) and
+@kbd{C-M-p} (@code{backward-list}) move over one (or @var{n})
+parenthetical groupings, skipping blithely over any amount of text
+that doesn't include meaningful parentheses (symbols, strings, etc.).
-@item defun-close
-On a brace that closes a function definition.
+@kindex C-M-u
+@findex backward-up-list
+ @kbd{C-M-n} and @kbd{C-M-p} try to stay at the same level in the
+parenthesis structure. To move @emph{up} one (or @var{n}) levels, use
+@kbd{C-M-u} (@code{backward-up-list}). @kbd{C-M-u} moves backward up
+past one unmatched opening delimiter. A positive argument serves as a
+repeat count; a negative argument reverses the direction of motion, so
+that the command moves forward and up one or more levels.
-@item defun-block-intro
-In the first line in a top-level defun.
+@kindex C-M-d
+@findex down-list
+ To move @emph{down} in the parenthesis structure, use @kbd{C-M-d}
+(@code{down-list}). In Lisp mode, where @samp{(} is the only opening
+delimiter, this is nearly the same as searching for a @samp{(}. An
+argument specifies the number of levels to go down.
-@item class-open
-On a brace that opens a class definition.
+@node Matching
+@subsection Automatic Display Of Matching Parentheses
+@cindex matching parentheses
+@cindex parentheses, displaying matches
-@item class-close
-On a brace that closes a class definition.
+ The Emacs parenthesis-matching feature is designed to show
+automatically how parentheses (and other matching delimiters) match in
+the text. Whenever you type a self-inserting character that is a
+closing delimiter, the cursor moves momentarily to the location of the
+matching opening delimiter, provided that is on the screen. If it is
+not on the screen, Emacs displays some of the text near it in the echo
+area. Either way, you can tell which grouping you are closing off.
-@item inline-open
-On a brace that opens an in-class inline method.
+ If the opening delimiter and closing delimiter are mismatched---such
+as in @samp{[x)}---a warning message is displayed in the echo area.
-@item inline-close
-On a brace that closes an in-class inline method.
+@vindex blink-matching-paren
+@vindex blink-matching-paren-distance
+@vindex blink-matching-delay
+ Three variables control parenthesis match display:
-@item extern-lang-open
-On a brace that opens an external language block.
+ @code{blink-matching-paren} turns the feature on or off: @code{nil}
+disables it, but the default is @code{t} to enable match display.
-@item extern-lang-close
-On a brace that closes an external language block.
+ @code{blink-matching-delay} says how many seconds to leave the
+cursor on the matching opening delimiter, before bringing it back to
+the real location of point; the default is 1, but on some systems it
+is useful to specify a fraction of a second.
-@item func-decl-cont
-The region between a function definition's argument list and the defun
-opening brace (excluding K&R function definitions). In C, you cannot
-put anything but whitespace and comments between them; in C++ and Java,
-@code{throws} declarations and other things can appear in this context.
+ @code{blink-matching-paren-distance} specifies how many characters
+back to search to find the matching opening delimiter. If the match
+is not found in that distance, scanning stops, and nothing is displayed.
+This is to prevent the scan for the matching delimiter from wasting
+lots of time when there is no match. The default is 25600.
-@item knr-argdecl-intro
-On the first line of a K&R C argument declaration.
+@cindex Show Paren mode
+@cindex highlighting matching parentheses
+@findex show-paren-mode
+ Show Paren mode provides a more powerful kind of automatic matching.
+Whenever point is after a closing delimiter, that delimiter and its
+matching opening delimiter are both highlighted; otherwise, if point
+is before an opening delimiter, the matching closing delimiter is
+highlighted. (There is no need to highlight the opening delimiter in
+that case, because the cursor appears on top of that character.) Use
+the command @kbd{M-x show-paren-mode} to enable or disable this mode.
+
+ Show Paren mode uses the faces @code{show-paren-match} and
+@code{show-paren-mismatch} to highlight parentheses; you can customize
+them to control how highlighting looks. @xref{Face Customization}.
-@item knr-argdecl
-In one of the subsequent lines in a K&R C argument declaration.
+@node Comments
+@section Manipulating Comments
+@cindex comments
-@item topmost-intro
-On the first line in a topmost construct definition.
+ Because comments are such an important part of programming, Emacs
+provides special commands for editing and inserting comments. It can
+also do spell checking on comments with Flyspell Prog mode
+(@pxref{Spelling}).
-@item topmost-intro-cont
-On the topmost definition continuation lines.
+@menu
+* Comment Commands:: Inserting, killing, and aligning comments.
+* Multi-Line Comments:: Commands for adding and editing multi-line comments.
+* Options for Comments::Customizing the comment features.
+@end menu
-@item member-init-intro
-On the first line in a member initialization list.
+@node Comment Commands
+@subsection Comment Commands
+@cindex indentation for comments
+@cindex alignment for comments
-@item member-init-cont
-On one of the subsequent member initialization list lines.
+ The comment commands in this table insert, kill and align comments.
+They are described in this section and following sections.
-@item inher-intro
-On the first line of a multiple inheritance list.
-
-@item inher-cont
-On one of the subsequent multiple inheritance lines.
-
-@item block-open
-On a statement block open brace.
-
-@item block-close
-On a statement block close brace.
-
-@item brace-list-open
-On the opening brace of an @code{enum} or @code{static} array list.
-
-@item brace-list-close
-On the closing brace of an @code{enum} or @code{static} array list.
-
-@item brace-list-intro
-On the first line in an @code{enum} or @code{static} array list.
-
-@item brace-list-entry
-On one of the subsequent lines in an @code{enum} or @code{static} array
-list.
-
-@item brace-entry-open
-On one of the subsequent lines in an @code{enum} or @code{static} array
-list, when the line begins with an open brace.
-
-@item statement
-On an ordinary statement.
-
-@item statement-cont
-On a continuation line of a statement.
-
-@item statement-block-intro
-On the first line in a new statement block.
-
-@item statement-case-intro
-On the first line in a @code{case} ``block.''
-
-@item statement-case-open
-On the first line in a @code{case} block starting with brace.
-
-@item inexpr-statement
-On a statement block inside an expression. This is used for a GNU
-extension to the C language, and for Pike special functions that take a
-statement block as an argument.
-
-@item inexpr-class
-On a class definition inside an expression. This is used for anonymous
-classes and anonymous array initializers in Java.
-
-@item substatement
-On the first line after an @code{if}, @code{while}, @code{for},
-@code{do}, or @code{else}.
-
-@item substatement-open
-On the brace that opens a substatement block.
-
-@item case-label
-On a @code{case} or @code{default} label.
-
-@item access-label
-On a C++ @code{private}, @code{protected}, or @code{public} access label.
-
-@item label
-On any ordinary label.
-
-@item do-while-closure
-On the @code{while} that ends a @code{do}-@code{while} construct.
-
-@item else-clause
-On the @code{else} of an @code{if}-@code{else} construct.
-
-@item catch-clause
-On the @code{catch} and @code{finally} lines in
-@code{try}@dots{}@code{catch} constructs in C++ and Java.
-
-@item comment-intro
-On a line containing only a comment introduction.
-
-@item arglist-intro
-On the first line in an argument list.
-
-@item arglist-cont
-On one of the subsequent argument list lines when no arguments follow on
-the same line as the arglist opening parenthesis.
-
-@item arglist-cont-nonempty
-On one of the subsequent argument list lines when at least one argument
-follows on the same line as the arglist opening parenthesis.
-
-@item arglist-close
-On the closing parenthesis of an argument list.
-
-@item stream-op
-On one of the lines continuing a stream operator construct.
-
-@item inclass
-On a construct that is nested inside a class definition. The
-indentation is relative to the open brace of the class definition.
-
-@item inextern-lang
-On a construct that is nested inside an external language block.
-
-@item inexpr-statement
-On the first line of statement block inside an expression. This is used
-for the GCC extension to C that uses the syntax @code{(@{ @dots{} @})}.
-It is also used for the special functions that takes a statement block
-as an argument in Pike.
-
-@item inexpr-class
-On the first line of a class definition inside an expression. This is
-used for anonymous classes and anonymous array initializers in Java.
-
-@item cpp-macro
-On the start of a cpp macro.
-
-@item friend
-On a C++ @code{friend} declaration.
-
-@item objc-method-intro
-On the first line of an Objective-C method definition.
-
-@item objc-method-args-cont
-On one of the lines continuing an Objective-C method definition.
-
-@item objc-method-call-cont
-On one of the lines continuing an Objective-C method call.
-
-@item inlambda
-Like @code{inclass}, but used inside lambda (i.e. anonymous) functions. Only
-used in Pike.
-
-@item lambda-intro-cont
-On a line continuing the header of a lambda function, between the
-@code{lambda} keyword and the function body. Only used in Pike.
-@end table
-
-@node Variables for C Indent
-@subsubsection Variables for C Indentation
-
- This section describes additional variables which control the
-indentation behavior of C mode and related mode.
-
-@table @code
-@item c-offsets-alist
-@vindex c-offsets-alist
-Association list of syntactic symbols and their indentation offsets.
-You should not set this directly, only with @code{c-set-offset}.
-@xref{Changing Indent Style}, for details.
-
-@item c-style-alist
-@vindex c-style-alist
-Variable for defining indentation styles; see below.
-
-@item c-basic-offset
-@vindex c-basic-offset
-Amount of basic offset used by @code{+} and @code{-} symbols in
-@code{c-offsets-alist}.@refill
-
-@item c-special-indent-hook
-@vindex c-special-indent-hook
-Hook for user-defined special indentation adjustments. This hook is
-called after a line is indented by C mode and related modes.
-@end table
-
- The variable @code{c-style-alist} specifies the predefined indentation
-styles. Each element has form @code{(@var{name}
-@var{variable-setting}@dots{})}, where @var{name} is the name of the
-style. Each @var{variable-setting} has the form @code{(@var{variable}
-. @var{value})}; @var{variable} is one of the customization variables
-used by C mode, and @var{value} is the value for that variable when
-using the selected style.
-
- When @var{variable} is @code{c-offsets-alist}, that is a special case:
-@var{value} is appended to the front of the value of @code{c-offsets-alist}
-instead of replacing that value outright. Therefore, it is not necessary
-for @var{value} to specify each and every syntactic symbol---only those
-for which the style differs from the default.
-
- The indentation of lines containing only comments is also affected by
-the variable @code{c-comment-only-line-offset} (@pxref{Comments in C}).
-
-@node C Indent Styles
-@subsubsection C Indentation Styles
-@cindex c indentation styles
-
- A @dfn{C style} is a collection of indentation style customizations.
-Emacs comes with several predefined indentation styles for C and related
-modes, including @code{gnu}, @code{k&r}, @code{bsd}, @code{stroustrup},
-@code{linux}, @code{python}, @code{java}, @code{whitesmith},
-@code{ellemtel}, @code{cc-mode}, and @code{user}.
-
-@findex c-set-style
-@vindex c-default-style
- To choose the style you want, use the command @kbd{M-x c-set-style}.
-Specify a style name as an argument (case is not significant in C style
-names). The chosen style only affects newly visited buffers, not those
-you are already editing. You can also set the variable
-@code{c-default-style} to specify the style for various major modes.
-Its value should be an alist, in which each element specifies one major
-mode and which indentation style to use for it. For example,
-
-@example
-(setq c-default-style
- '((java-mode . "java") (other . "gnu")))
-@end example
-
-@noindent
-specifies an explicit choice for Java mode, and the default @samp{gnu}
-style for the other C-like modes.
-
- The style @code{gnu} defines the formatting recommend by the GNU
-Project; it is the default, so as to encourage the indentation we
-recommend. However, if you make changes in variables such as
-@code{c-basic-offset} and @code{c-offsets-alist} in your
-@file{~/.emacs} file, your changes override the what @code{gnu} style
-says.
-
-@findex c-add-style
- To define a new C indentation style, call the function
-@code{c-add-style}:
-
-@example
-(c-add-style @var{name} @var{values} @var{use-now})
-@end example
-
-@noindent
-Here @var{name} is the name of the new style (a string), and
-@var{values} is an alist whose elements have the form
-@code{(@var{variable} . @var{value})}. The variables you specify should
-be among those documented in @ref{Variables for C Indent}.
-
- If @var{use-now} is non-@code{nil}, @code{c-add-style} selects the new
-style after defining it.
-
-@node Matching
-@section Automatic Display Of Matching Parentheses
-@cindex matching parentheses
-@cindex parentheses, displaying matches
-
- The Emacs parenthesis-matching feature is designed to show
-automatically how parentheses match in the text. Whenever you type a
-self-inserting character that is a closing delimiter, the cursor moves
-momentarily to the location of the matching opening delimiter, provided
-that is on the screen. If it is not on the screen, some text near it is
-displayed in the echo area. Either way, you can tell what grouping is
-being closed off.
-
- In Lisp, automatic matching applies only to parentheses. In C, it
-applies to braces and brackets too. Emacs knows which characters to regard
-as matching delimiters based on the syntax table, which is set by the major
-mode. @xref{Syntax}.
-
- If the opening delimiter and closing delimiter are mismatched---such as
-in @samp{[x)}---a warning message is displayed in the echo area. The
-correct matches are specified in the syntax table.
-
-@vindex blink-matching-paren
-@vindex blink-matching-paren-distance
-@vindex blink-matching-delay
- Three variables control parenthesis match display.
-@code{blink-matching-paren} turns the feature on or off; @code{nil}
-turns it off, but the default is @code{t} to turn match display on.
-@code{blink-matching-delay} says how many seconds to wait; the default
-is 1, but on some systems it is useful to specify a fraction of a
-second. @code{blink-matching-paren-distance} specifies how many
-characters back to search to find the matching opening delimiter. If
-the match is not found in that far, scanning stops, and nothing is
-displayed. This is to prevent scanning for the matching delimiter from
-wasting lots of time when there is no match. The default is 25600.
-
-@cindex Show Paren mode
-@cindex highlighting matching parentheses
-@findex show-paren-mode
- Show Paren mode provides a more powerful kind of automatic
-parenthesis matching. Whenever point is after a close parenthesis,
-the close parenthesis and its matching open parenthesis are both
-highlighted; otherwise, if point is before an open parenthesis, the
-matching close parenthesis is highlighted. (There is no need to
-highlight the open parenthesis after point because the cursor appears
-on top of that character.) Use the command @kbd{M-x show-paren-mode}
-to enable or disable this mode.
-
- By default, @code{show-paren-mode} uses colors to highlight the
-parentheses. However, if your display doesn't support colors, you can
-customize the faces @code{show-paren-match-face} and
-@code{show-paren-mismatch-face} to use other attributes, such as bold or
-underline. @xref{Face Customization}.
-
-@node Comments
-@section Manipulating Comments
-@cindex comments
-
- Because comments are such an important part of programming, Emacs
-provides special commands for editing and inserting comments.
-
-@menu
-* Comment Commands::
-* Multi-Line Comments::
-* Options for Comments::
-@end menu
-
-@node Comment Commands
-@subsection Comment Commands
-@cindex indentation for comments
-
- The comment commands in this table insert, kill and align comments.
-They are described in this section and following sections.
-
-@table @kbd
-@item M-;
+@table @asis
+@item @kbd{M-;}
Insert or realign comment on current line; alternatively, comment or
uncomment the region (@code{comment-dwim}).
-@item C-u M-;
+@item @kbd{C-u M-;}
Kill comment on current line (@code{comment-kill}).
-@item C-x ;
+@item @kbd{C-x ;}
Set comment column (@code{comment-set-column}).
-@item C-M-j
+@item @kbd{C-M-j}
+@itemx @kbd{M-j}
Like @key{RET} followed by inserting and aligning a comment
-(@code{comment-indent-new-line}).
-@item M-x comment-region
+(@code{comment-indent-new-line}). @xref{Multi-Line Comments}.
+@item @kbd{M-x comment-region}
+@itemx @kbd{C-c C-c} (in C-like modes)
Add or remove comment delimiters on all the lines in the region.
@end table
start with (the value of @code{comment-start}; see below). Point is
after that string, so you can insert the text of the comment right
away. If the major mode has specified a string to terminate comments,
-@kbd{M-;} inserts that too, to keep the syntax valid.
+@kbd{M-;} inserts that after point, to keep the syntax valid.
- If the text of the line extends past the comment column, then the
-comment start string is indented to a suitable boundary (usually, at
-least one space is inserted).
+ If the text of the line extends past the comment column, this
+command aligns the comment start string to a suitable boundary
+(usually, at least one space is inserted).
You can also use @kbd{M-;} to align an existing comment. If a line
-already contains the comment-start string, @kbd{M-;} reindents it to
+already contains the comment-start string, @kbd{M-;} realigns it to
the conventional alignment and moves point after it. (Exception:
comments starting in column 0 are not moved.) Even when an existing
comment is properly aligned, @kbd{M-;} is still useful for moving
is a comment, it removes comment delimiters from each; otherwise, it
adds comment delimiters to each.) If you are not using Transient Mark
mode, then you should use the commands @code{comment-region} and
-@code{uncomment-region} to do these jobs (@pxref{Multi-Line Comments}).
+@code{uncomment-region} to do these jobs (@pxref{Multi-Line Comments}),
+or else enable Transient Mark mode momentarily (@pxref{Momentary Mark}).
A prefix argument used in these circumstances specifies how many
comment delimiters to add or how many to delete.
- Some major modes have special rules for indenting certain kinds of
+ Some major modes have special rules for aligning certain kinds of
comments in certain contexts. For example, in Lisp code, comments which
start with two semicolons are indented as if they were lines of code,
instead of at the comment column. Comments which start with three
(1+ x)) ; This line adds one.
@end example
- In C code, a comment preceded on its line by nothing but whitespace
-is indented like a line of code.
+ For C-like modes, you can configure the exact effect of @kbd{M-;}
+more flexibly than for most buffers by setting the variables
+@code{c-indent-comment-alist} and
+@code{c-indent-comments-syntactically-p}. For example, on a line
+ending in a closing brace, @kbd{M-;} puts the comment one space after
+the brace rather than at @code{comment-column}. For full details see
+@ref{Comment Commands,,, ccmode, The CC Mode Manual}.
@node Multi-Line Comments
@subsection Multiple Lines of Comments
@kindex C-M-j
+@kindex M-j
@cindex blank lines in programs
@findex comment-indent-new-line
- If you are typing a comment and wish to continue it on another line,
-you can use the command @kbd{C-M-j} (@code{comment-indent-new-line}).
-This terminates the comment you are typing, creates a new blank line
-afterward, and begins a new comment indented under the old one. When
-Auto Fill mode is on, going past the fill column while typing a comment
-causes the comment to be continued in just this fashion. If point is
-not at the end of the line when @kbd{C-M-j} is typed, the text on
-the rest of the line becomes part of the new comment line.
+ If you are typing a comment and wish to continue it on another line,
+you can use the command @kbd{C-M-j} or @kbd{M-j}
+(@code{comment-indent-new-line}). If @code{comment-multi-line}
+(@pxref{Options for Comments}) is non-@code{nil}, it moves to a new
+line within the comment. Otherwise it closes the comment and starts a
+new comment on a new line. When Auto Fill mode is on, going past the
+fill column while typing a comment causes the comment to be continued
+in just this fashion.
+
+@kindex C-c C-c (C mode)
@findex comment-region
To turn existing lines into comment lines, use the @kbd{M-x
-comment-region} command. It adds comment delimiters to the lines that start
-in the region, thus commenting them out. With a negative argument, it
-does the opposite---it deletes comment delimiters from the lines in the
-region.
+comment-region} command (or type @kbd{C-c C-c} in C-like modes). It
+adds comment delimiters to the lines that start in the region, thus
+commenting them out. With a negative argument, it does the
+opposite---it deletes comment delimiters from the lines in the region.
With a positive argument, @code{comment-region} duplicates the last
-character of the comment start sequence it adds; the argument specifies
-how many copies of the character to insert. Thus, in Lisp mode,
-@kbd{C-u 2 M-x comment-region} adds @samp{;;} to each line. Duplicating
-the comment delimiter is a way of calling attention to the comment. It
-can also affect how the comment is indented. In Lisp, for proper
-indentation, you should use an argument of two or three, if between defuns;
-if within a defun, it must be three.
+character of the comment start sequence it adds; the argument
+specifies how many copies of the character to insert. Thus, in Lisp
+mode, @kbd{C-u 2 M-x comment-region} adds @samp{;;} to each line.
+Duplicating the comment delimiter is a way of calling attention to the
+comment. It can also affect how the comment is aligned or indented.
+In Lisp, for proper indentation, you should use an argument of two or
+three, if between defuns; if within a defun, it must be three.
+
+ You can configure C Mode such that when you type a @samp{/} at the
+start of a line in a multi-line block comment, this closes the
+comment. Enable the @code{comment-close-slash} clean-up for this.
+@xref{Clean-ups,,, ccmode, The CC Mode Manual}.
@node Options for Comments
@subsection Options Controlling Comments
@vindex comment-column
@kindex C-x ;
@findex comment-set-column
- The comment column is stored in the variable @code{comment-column}. You
-can set it to a number explicitly. Alternatively, the command @kbd{C-x ;}
-(@code{comment-set-column}) sets the comment column to the column point is
-at. @kbd{C-u C-x ;} sets the comment column to match the last comment
-before point in the buffer, and then does a @kbd{M-;} to align the
-current line's comment under the previous one.
+ The @dfn{comment column}, the column at which Emacs tries to place
+comments, is stored in the variable @code{comment-column}. You can
+set it to a number explicitly. Alternatively, the command @kbd{C-x ;}
+(@code{comment-set-column}) sets the comment column to the column
+point is at. @kbd{C-u C-x ;} sets the comment column to match the
+last comment before point in the buffer, and then does a @kbd{M-;} to
+align the current line's comment under the previous one.
The variable @code{comment-column} is per-buffer: setting the variable
in the normal fashion affects only the current buffer, but there is a
The comment commands recognize comments based on the regular
expression that is the value of the variable @code{comment-start-skip}.
Make sure this regexp does not match the null string. It may match more
-than the comment starting delimiter in the strictest sense of the word;
-for example, in C mode the value of the variable is
-@c This stops M-q from breaking the line inside that @code.
-@code{@w{"/\\*+ *\\|//+ *""}}, which matches extra stars and spaces
-after the @samp{/*} itself, and accepts C++ style comments also.
-(Note that @samp{\\} is needed in Lisp syntax to include a @samp{\} in
-the string, which is needed to deny the first star its special meaning
-in regexp syntax. @xref{Regexps}.)
-
-@vindex comment-start
-@vindex comment-end
- When a comment command makes a new comment, it inserts the value of
-@code{comment-start} to begin it. The value of @code{comment-end} is
-inserted after point, so that it will follow the text that you will insert
-into the comment. In C mode, @code{comment-start} has the value
-@w{@code{"/* "}} and @code{comment-end} has the value @w{@code{" */"}}.
-
-@vindex comment-padding
- The variable @code{comment-padding} specifies how many spaces
-@code{comment-region} should insert on each line between the
-comment delimiter and the line's original text. The default is 1,
-to insert one space.
-
-@vindex comment-multi-line
- The variable @code{comment-multi-line} controls how @kbd{C-M-j}
-(@code{indent-new-comment-line}) behaves when used inside a comment. If
-@code{comment-multi-line} is @code{nil}, as it normally is, then the
-comment on the starting line is terminated and a new comment is started
-on the new following line. If @code{comment-multi-line} is not
-@code{nil}, then the new following line is set up as part of the same
-comment that was found on the starting line. This is done by not
-inserting a terminator on the old line, and not inserting a starter on
-the new line. In languages where multi-line comments work, the choice
-of value for this variable is a matter of taste.
-
-@vindex comment-indent-function
- The variable @code{comment-indent-function} should contain a function
-that will be called to compute the indentation for a newly inserted
-comment or for aligning an existing comment. It is set differently by
-various major modes. The function is called with no arguments, but with
-point at the beginning of the comment, or at the end of a line if a new
-comment is to be inserted. It should return the column in which the
-comment ought to start. For example, in Lisp mode, the indent hook
-function bases its decision on how many semicolons begin an existing
-comment, and on the code in the preceding lines.
-
-@node Balanced Editing
-@section Editing Without Unbalanced Parentheses
-
-@table @kbd
-@item M-(
-Put parentheses around next sexp(s) (@code{insert-parentheses}).
-@item M-)
-Move past next close parenthesis and reindent
-(@code{move-past-close-and-reindent}).
-@end table
-
-@kindex M-(
-@kindex M-)
-@findex insert-parentheses
-@findex move-past-close-and-reindent
- The commands @kbd{M-(} (@code{insert-parentheses}) and @kbd{M-)}
-(@code{move-past-close-and-reindent}) are designed to facilitate a style
-of editing which keeps parentheses balanced at all times. @kbd{M-(}
-inserts a pair of parentheses, either together as in @samp{()}, or, if
-given an argument, around the next several sexps. It leaves point after
-the open parenthesis. The command @kbd{M-)} moves past the close
-parenthesis, deleting any indentation preceding it, and indenting with
-@kbd{C-j} after it.
-
- For example, instead of typing @kbd{( F O O )}, you can type @kbd{M-(
-F O O}, which has the same effect except for leaving the cursor before
-the close parenthesis.
-
-@vindex parens-require-spaces
- @kbd{M-(} may insert a space before the open parenthesis, depending on
-the syntax class of the preceding character. Set
-@code{parens-require-spaces} to @code{nil} value if you wish to inhibit
-this.
-
-@findex check-parens
-@cindex unbalanced parentheses and quotes
- You can use @kbd{M-x check-parens} to find any unbalanced
-parentheses and unbalanced string quotes in a buffer.
-
-@node Symbol Completion
-@section Completion for Symbol Names
-@cindex completion (symbol names)
-
- Usually completion happens in the minibuffer. But one kind of completion
-is available in all buffers: completion for symbol names.
-
-@kindex M-TAB
- The character @kbd{M-@key{TAB}} runs a command to complete the partial
-symbol before point against the set of meaningful symbol names. Any
-additional characters determined by the partial name are inserted at
-point.
-
- If the partial name in the buffer has more than one possible completion
-and they have no additional characters in common, a list of all possible
-completions is displayed in another window.
-
-@cindex tags-based completion
-@cindex Info index completion
-@findex complete-symbol
- In most programming language major modes, @kbd{M-@key{TAB}} runs the
-command @code{complete-symbol}, which provides two kinds of completion.
-Normally it does completion based on a tags table (@pxref{Tags}); with a
-numeric argument (regardless of the value), it does completion based on
-the names listed in the Info file indexes for your language. Thus, to
-complete the name of a symbol defined in your own program, use
-@kbd{M-@key{TAB}} with no argument; to complete the name of a standard
-library function, use @kbd{C-u M-@key{TAB}}. Of course, Info-based
-completion works only if there is an Info file for the standard library
-functions of your language, and only if it is installed at your site.
-
-@cindex Lisp symbol completion
-@cindex completion (Lisp symbols)
-@findex lisp-complete-symbol
- In Emacs-Lisp mode, the name space for completion normally consists of
-nontrivial symbols present in Emacs---those that have function
-definitions, values or properties. However, if there is an
-open-parenthesis immediately before the beginning of the partial symbol,
-only symbols with function definitions are considered as completions.
-The command which implements this is @code{lisp-complete-symbol}.
-
- In Text mode and related modes, @kbd{M-@key{TAB}} completes words
-based on the spell-checker's dictionary. @xref{Spelling}.
-
-@node Which Function
-@section Which Function Mode
-
- Which Function mode is a minor mode that displays the current function
-name in the mode line, as you move around in a buffer.
-
-@findex which-function-mode
-@vindex which-func-modes
- To enable (or disable) Which Function mode, use the command @kbd{M-x
-which-function-mode}. This command is global; it applies to all
-buffers, both existing ones and those yet to be created. However, this
-only affects certain major modes, those listed in the value of
-@code{which-func-modes}. (If the value is @code{t}, then Which Function
-mode applies to all major modes that know how to support it---which are
-the major modes that support Imenu.)
-
-@node Hideshow
-@section Hideshow minor mode
-
-@findex hs-minor-mode
- Hideshow minor mode provides selective display of portions of a
-file, known as @dfn{blocks}. You can use @kbd{M-x hs-minor-mode} to
-enable or disable this mode, or add @code{hs-minor-mode} to the mode
-hook for certain major modes in order to enable it automatically for
-those modes.
-
- Just what constitutes a block depends on the major mode. In C mode
-or C++ mode, they are delimited by braces, while in Lisp mode and
-similar modes they are delimited by parentheses. Multi-line comments
-also count as blocks.
-
-@findex hs-hide-all
-@findex hs-hide-block
-@findex hs-show-all
-@findex hs-show-block
-@findex hs-show-region
-@findex hs-hide-level
-@findex hs-minor-mode
-@kindex C-c @@ C-h
-@kindex C-c @@ C-s
-@kindex C-c @@ C-M-h
-@kindex C-c @@ C-M-s
-@kindex C-c @@ C-r
-@kindex C-c @@ C-l
-@kindex S-Mouse-2
-@table @kbd
-@item C-c @@ C-h
-Hide the current block (@code{hs-hide-block}).
-@item C-c @@ C-s
-Show the current block (@code{hs-show-block}).
-@item C-c @@ C-c
-Either hide or show the current block (@code{hs-toggle-hiding})
-@item S-Mouse-2
-Either hide or show the block you click on (@code{hs-mouse-toggle-hiding})
-@item C-c @@ C-M-h
-Hide all top-level blocks (@code{hs-hide-all}).
-@item C-c @@ C-M-s
-Show everything in the buffer (@code{hs-show-all}).
-@item C-c @@ C-l
-Hide all blocks @var{n} levels below this block
-(@code{hs-hide-level}).
-@end table
-
-@vindex hs-hide-comments-when-hiding-all
-@vindex hs-isearch-open
-@vindex hs-special-modes-alist
- These user options exist for customizing Hideshow mode.
-
-@table @code
-@item hs-hide-comments-when-hiding-all
-Non-@code{nil} says that @kbd{hs-hide-all} should hide comments too.
-@item hs-isearch-open
-Specifies what kind of hidden blocks to open in Isearch mode.
-@item hs-special-modes-alist
-Specifies
-Initializes Hideshow variables for different modes.
-@end table
-
-@node Glasses
-@section Glasses minor mode
-@cindex Glasses mode
-@cindex identifiers, making long ones readable
-@cindex StudlyCaps, making them readable
-@findex glasses-mode
-
- Glasses minor mode makes @samp{unreadableIdentifiersLikeThis}
-readable by altering the display. It can do this in two different
-ways: by displaying underscores between an lower-case letter and the
-following capital letter, or by emboldening the capital letters. It
-does not alter the buffer text, only the way they display, so you can
-use it even on read-only buffers. You can use the command @kbd{M-x
-glasses-mode} to enable or disable the mode; you can also add
-@code{glasses-mode} to the mode hook of appropriate programming
-language major modes.
-
-@node Documentation
-@section Documentation Commands
-
- As you edit Lisp code to be run in Emacs, the commands @kbd{C-h f}
-(@code{describe-function}) and @kbd{C-h v} (@code{describe-variable}) can
-be used to print documentation of functions and variables that you want to
-call. These commands use the minibuffer to read the name of a function or
-variable to document, and display the documentation in a window.
-
- For extra convenience, these commands provide default arguments based on
-the code in the neighborhood of point. @kbd{C-h f} sets the default to the
-function called in the innermost list containing point. @kbd{C-h v} uses
-the symbol name around or adjacent to point as its default.
-
-@cindex Eldoc mode
-@findex eldoc-mode
- For Emacs Lisp code, you can also use Eldoc mode. This minor mode
-constantly displays in the echo area the argument list for the function
-being called at point. (In other words, it finds the function call that
-point is contained in, and displays the argument list of that function.)
-Eldoc mode applies in Emacs Lisp and Lisp Interaction modes only. Use
-the command @kbd{M-x eldoc-mode} to enable or disable this feature.
-
-@findex info-lookup-symbol
-@findex info-lookup-file
-@kindex C-h C-i
- For C, Lisp, and other languages, you can use @kbd{C-h C-i}
-(@code{info-lookup-symbol}) to view the Info documentation for a symbol.
-You specify the symbol with the minibuffer; by default, it uses the
-symbol that appears in the buffer at point. The major mode determines
-where to look for documentation for the symbol---which Info files and
-which indices. You can also use @kbd{M-x info-lookup-file} to look for
-documentation for a file name. Currently this supports the following
-modes: Awk, Autoconf, Bison, C, Emacs Lisp, LaTeX, M4,
-Makefile, Octave, Perl, Scheme and Texinfo, provided you have installed
-the relevant Info files, which are typically available with the appropriate GNU
-package.
-
-@findex manual-entry
-@cindex manual pages
- You can read the ``man page'' for an operating system command, library
-function, or system call, with the @kbd{M-x manual-entry} command. It
-runs the @code{man} program to format the man page, and runs it
-asynchronously if your system permits, so that you can keep on editing
-while the page is being formatted. (MS-DOS and MS-Windows 3 do not
-permit asynchronous subprocesses, so on these systems you cannot edit
-while Emacs waits for @code{man} to exit.) The result goes in a buffer
-named @samp{*Man @var{topic}*}. These buffers use a special major mode,
-Man mode, that facilitates scrolling and examining other manual pages.
-For details, type @kbd{C-h m} while in a man page buffer.
-
-@cindex sections of manual pages
- Man pages are classified into @dfn{sections}; sometimes there are
-man pages with the same name in different sections. To read a man
-page from a specific section, type @samp{@var{topic}(@var{section})} or
-@samp{@var{section} @var{topic}} when @kbd{M-x manual-entry} prompts
-for the topic. For example, to read the man page for the C library
-function @code{chmod} (as opposed to a command by the same name), type
-@kbd{M-x manual-entry @key{RET} chmod(2v) @key{RET}} (assuming
-@code{chmod} is in section @samp{2v}).
-
- If you do not specify a section, the results depend on how the
-@code{man} command works on your system. Some of them display only
-the first man page they find. Others display all man pages that have
-the specified name, so you can page between them with the @kbd{M-n}
-and @kbd{M-p} keys. The mode line shows how many manual pages are
-available in the Man buffer.
-
-@vindex Man-fontify-manpage-flag
- For a long man page, setting the faces properly can take substantial
-time. By default, Emacs uses faces in man pages if Emacs can display
-different fonts or colors. You can turn off use of faces in man pages
-by setting the variable @code{Man-fontify-manpage-flag} to @code{nil}.
-
-@findex Man-fontify-manpage
- If you insert the text of a man page into an Emacs buffer in some
-other fashion, you can use the command @kbd{M-x Man-fontify-manpage} to
-perform the same conversions that @kbd{M-x manual-entry} does.
-
-@findex woman
-@cindex manual pages, on MS-DOS/MS-Windows
- An alternative way of reading manual pages is the @kbd{M-x woman}
-command@footnote{The name of the command, @code{woman}, is an acronym
-for ``w/o (without) man,'' since it doesn't use the @code{man}
-program.}. Unlike @kbd{M-x man}, it does not run any external
-programs to format and display the man pages; instead it does the job
-in Emacs Lisp, so it works on systems such as MS-Windows, where the
-@code{man} program and other the programs it needs are not readily
-available. @kbd{M-x woman} prompts for a name of a manual page, and
-provides completion based on the list of manual pages that are
-installed on your machine; the list of available manual pages is
-computed automatically the first time you invoke @code{woman}. The
-word at point in the current buffer is used to suggest the default
-name of the manual page.
-
- With a numeric argument, @kbd{M-x woman} recomputes the list of the
-manual pages used for completion. This is useful if you add or delete
-manual pages.
-
- If you type a name of a manual page and @kbd{M-x woman} finds that
-several manual pages by the same name exist in different sections, it
-pops up a window with possible candidates asking you to choose one of
-them.
-
-@vindex woman-manpath
- By default, @kbd{M-x woman} looks up the manual pages in directories
-listed by the @code{MANPATH} environment variable. (If @code{MANPATH}
-is not set, @code{woman} uses a suitable default value, which can be
-customized.) More precisely, @code{woman} looks for subdirectories that
-match the shell wildcard @file{man*} in each one of these directories,
-and tries to find the manual pages in those subdirectories. When first
-invoked, @kbd{M-x woman} converts the value of @code{MANPATH} to a list
-of directory names and stores that list in the @code{woman-manpath}
-variable. By changing the value of this variable, you can customize the
-list of directories where @code{woman} looks for manual pages.
-
-@vindex woman-path
- In addition, you can augment the list of directories searched by
-@code{woman} by setting the value of the @code{woman-path} variable.
-This variable should hold a list of specific directories which
-@code{woman} should search, in addition to those in
-@code{woman-manpath}. Unlike @code{woman-manpath}, the directories in
-@code{woman-path} are searched for the manual pages, not for @file{man*}
-subdirectories.
-
-@findex woman-find-file
- Occasionally, you might need to display manual pages that are not in
-any of the directories listed by @code{woman-manpath} and
-@code{woman-path}. The @kbd{M-x woman-find-file} command prompts for a
-name of a manual page file, with completion, and then formats and
-displays that file like @kbd{M-x woman} does.
-
-@vindex woman-dired-keys
- First time you invoke @kbd{M-x woman}, it defines the Dired @kbd{W}
-key to run the @code{woman-find-file} command on the current line's
-file. You can disable this by setting the variable
-@code{woman-dired-keys} to @code{nil}. @xref{Dired}. In addition, the
-Tar-mode @kbd{w} key is bound to @code{woman-find-file} on the current
-line's archive member.
-
- For more information about setting up and using @kbd{M-x woman}, see
-@ref{Top, WoMan, Browse UN*X Manual Pages WithOut Man, woman, The WoMan
-Manual}.
-
- Eventually the GNU project hopes to replace most man pages with
-better-organized manuals that you can browse with Info. @xref{Misc
-Help}. Since this process is only partially completed, it is still
-useful to read manual pages.
-
-@node Change Log
-@section Change Logs
-
-@cindex change log
-@kindex C-x 4 a
-@findex add-change-log-entry-other-window
- The Emacs command @kbd{C-x 4 a} adds a new entry to the change log
-file for the file you are editing
-(@code{add-change-log-entry-other-window}). If that file is actually
-a backup file, it makes an entry appropriate for the file's
-parent---that is useful for making log entries for functions that
-have been deleted in the current version.
-
- A change log file contains a chronological record of when and why you
-have changed a program, consisting of a sequence of entries describing
-individual changes. Normally it is kept in a file called
-@file{ChangeLog} in the same directory as the file you are editing, or
-one of its parent directories. A single @file{ChangeLog} file can
-record changes for all the files in its directory and all its
-subdirectories.
-
- A change log entry starts with a header line that contains your name,
-your email address (taken from the variable @code{user-mail-address}),
-and the current date and time. Aside from these header lines, every
-line in the change log starts with a space or a tab. The bulk of the
-entry consists of @dfn{items}, each of which starts with a line starting
-with whitespace and a star. Here are two entries, both dated in May
-1993, each with two items:
-
-@iftex
-@medbreak
-@end iftex
-@smallexample
-1993-05-25 Richard Stallman <rms@@gnu.org>
-
- * man.el: Rename symbols `man-*' to `Man-*'.
- (manual-entry): Make prompt string clearer.
-
- * simple.el (blink-matching-paren-distance):
- Change default to 12,000.
-
-1993-05-24 Richard Stallman <rms@@gnu.org>
-
- * vc.el (minor-mode-map-alist): Don't use it if it's void.
- (vc-cancel-version): Doc fix.
-@end smallexample
-
- One entry can describe several changes; each change should have its
-own item. Normally there should be a blank line between items. When
-items are related (parts of the same change, in different places), group
-them by leaving no blank line between them. The second entry above
-contains two items grouped in this way.
-
- @kbd{C-x 4 a} visits the change log file and creates a new entry
-unless the most recent entry is for today's date and your name. It
-also creates a new item for the current file. For many languages, it
-can even guess the name of the function or other object that was
-changed.
-
-@vindex add-log-keep-changes-together
- When the option @code{add-log-keep-changes-together} is
-non-@code{nil}, @kbd{C-x 4 a} adds to any existing entry for the file
-rather than starting a new entry.
-
-@vindex change-log-version-info-enabled
-@vindex change-log-version-number-regexp-list
-@cindex file version in change log entries
- If the value of the variable @code{change-log-version-info-enabled}
-is non-@code{nil}, @kbd{C-x 4 a} ads the file's version number to the
-change log entry. It finds the version number by searching the first
-ten percent of the file, using regular expressions from the variable
-@code{change-log-version-number-regexp-list}.
-
-@cindex Change Log mode
-@findex change-log-mode
- The change log file is visited in Change Log mode. In this major
-mode, each bunch of grouped items counts as one paragraph, and each
-entry is considered a page. This facilitates editing the entries.
-@kbd{C-j} and auto-fill indent each new line like the previous line;
-this is convenient for entering the contents of an entry.
-
-@findex change-log-merge
- You can use the command @kbd{M-x change-log-merge} to merge other
-log files into a buffer in Change Log Mode, preserving the date
-ordering of entries.
-
-@findex change-log-redate
-@cindex converting change log date style
- Versions of Emacs before 20.1 used a different format for the time of
-the change log entry:
-
-@smallexample
-Fri May 25 11:23:23 1993 Richard Stallman <rms@@gnu.org>
-@end smallexample
-
-@noindent
-The @kbd{M-x change-log-redate} command converts all the old-style
-date entries in the change log file visited in the current buffer to
-the new format, to make the file uniform in style. This is handy when
-entries are contributed by many different people, some of whom use old
-versions of Emacs.
-
- Version control systems are another way to keep track of changes in your
-program and keep a change log. @xref{Log Buffer}.
-
-@node Authors
-@section @file{AUTHORS} files
-@cindex @file{AUTHORS} file
-
- Programs which have many contributors usually include a file named
-@file{AUTHORS} in their distribution, which lists the individual
-contributions. Emacs has a special command for maintaining the
-@file{AUTHORS} file that is part of the Emacs distribution.
-
-@findex authors
- The @kbd{M-x authors} command prompts for the name of the root of the
-Emacs source directory. It then scans @file{ChageLog} files and Lisp
-source files under that directory for information about authors of
-individual packages and people who made changes in source files, and
-puts the information it gleans into a buffer named @samp{*Authors*}.
-You can then edit the contents of that buffer and merge it with the
-exisiting @file{AUTHORS} file.
-
- Do not assume that this command finds all the contributors; don't
-assume that a person not listed in the output was not a contributor.
-If you merged in someone's contribution and did not put his name
-in the change log, he won't show up in @kbd{M-x authors} either.
-
-@node Tags
-@section Tags Tables
-@cindex tags table
-
- A @dfn{tags table} is a description of how a multi-file program is
-broken up into files. It lists the names of the component files and the
-names and positions of the functions (or other named subunits) in each
-file. Grouping the related files makes it possible to search or replace
-through all the files with one command. Recording the function names
-and positions makes possible the @kbd{M-.} command which finds the
-definition of a function by looking up which of the files it is in.
-
- Tags tables are stored in files called @dfn{tags table files}. The
-conventional name for a tags table file is @file{TAGS}.
-
- Each entry in the tags table records the name of one tag, the name of the
-file that the tag is defined in (implicitly), and the position in that file
-of the tag's definition.
-
- Just what names from the described files are recorded in the tags table
-depends on the programming language of the described file. They
-normally include all file names, functions and subroutines, and may
-also include global variables, data types, and anything else
-convenient. Each name recorded is called a @dfn{tag}.
-
-@cindex C++ class browser, tags
-@cindex tags, C++
-@cindex class browser, C++
-@cindex Ebrowse
- See also the Ebrowse facility, which is tailored for C++.
-@xref{Top,, Ebrowse, ebrowse, Ebrowse User's Manual}.
-
-@menu
-* Tag Syntax:: Tag syntax for various types of code and text files.
-* Create Tags Table:: Creating a tags table with @code{etags}.
-* Etags Regexps:: Create arbitrary tags using regular expressions.
-* Select Tags Table:: How to visit a tags table.
-* Find Tag:: Commands to find the definition of a specific tag.
-* Tags Search:: Using a tags table for searching and replacing.
-* List Tags:: Listing and finding tags defined in a file.
-@end menu
-
-@node Tag Syntax
-@subsection Source File Tag Syntax
-
- Here is how tag syntax is defined for the most popular languages:
-
-@itemize @bullet
-@item
-In C code, any C function or typedef is a tag, and so are definitions of
-@code{struct}, @code{union} and @code{enum}.
-@code{#define} macro definitions and @code{enum} constants are also
-tags, unless you specify @samp{--no-defines} when making the tags table.
-Similarly, global variables are tags, unless you specify
-@samp{--no-globals}. Use of @samp{--no-globals} and @samp{--no-defines}
-can make the tags table file much smaller.
-
-You can tag function declarations and external variables in addition
-to function definitions by giving the @samp{--declarations} option to
-@code{etags}.
-
-@item
-In C++ code, in addition to all the tag constructs of C code, member
-functions are also recognized, and optionally member variables if you
-use the @samp{--members} option. Tags for variables and functions in
-classes are named @samp{@var{class}::@var{variable}} and
-@samp{@var{class}::@var{function}}. @code{operator} definitions have
-tag names like @samp{operator+}.
-
-@item
-In Java code, tags include all the constructs recognized in C++, plus
-the @code{interface}, @code{extends} and @code{implements} constructs.
-Tags for variables and functions in classes are named
-@samp{@var{class}.@var{variable}} and @samp{@var{class}.@var{function}}.
-
-@item
-In La@TeX{} text, the argument of any of the commands @code{\chapter},
-@code{\section}, @code{\subsection}, @code{\subsubsection},
-@code{\eqno}, @code{\label}, @code{\ref}, @code{\cite}, @code{\bibitem},
-@code{\part}, @code{\appendix}, @code{\entry}, or @code{\index}, is a
-tag.@refill
-
-Other commands can make tags as well, if you specify them in the
-environment variable @env{TEXTAGS} before invoking @code{etags}. The
-value of this environment variable should be a colon-separated list of
-command names. For example,
-
-@example
-TEXTAGS="def:newcommand:newenvironment"
-export TEXTAGS
-@end example
-
-@noindent
-specifies (using Bourne shell syntax) that the commands @samp{\def},
-@samp{\newcommand} and @samp{\newenvironment} also define tags.
-
-@item
-In Lisp code, any function defined with @code{defun}, any variable
-defined with @code{defvar} or @code{defconst}, and in general the first
-argument of any expression that starts with @samp{(def} in column zero, is
-a tag.
-
-@item
-In Scheme code, tags include anything defined with @code{def} or with a
-construct whose name starts with @samp{def}. They also include variables
-set with @code{set!} at top level in the file.
-@end itemize
-
- Several other languages are also supported:
-
-@itemize @bullet
-
-@item
-In Ada code, functions, procedures, packages, tasks, and types are
-tags. Use the @samp{--packages-only} option to create tags for
-packages only.
-
-In Ada, the same name can be used for different kinds of entity
-(e.g.@:, for a procedure and for a function). Also, for things like
-packages, procedures and functions, there is the spec (i.e.@: the
-interface) and the body (i.e.@: the implementation). To make it
-easier to pick the definition you want, Ada tag name have suffixes
-indicating the type of entity:
-
-@table @samp
-@item /b
-package body.
-@item /f
-function.
-@item /k
-task.
-@item /p
-procedure.
-@item /s
-package spec.
-@item /t
-type.
-@end table
-
- Thus, @kbd{M-x find-tag @key{RET} bidule/b @key{RET}} will go
-directly to the body of the package @code{bidule}, while @kbd{M-x
-find-tag @key{RET} bidule @key{RET}} will just search for any tag
-@code{bidule}.
-
-@item
-In assembler code, labels appearing at the beginning of a line,
-followed by a colon, are tags.
-
-@item
-In Bison or Yacc input files, each rule defines as a tag the nonterminal
-it constructs. The portions of the file that contain C code are parsed
-as C code.
-
-@item
-In Cobol code, tags are paragraph names; that is, any word starting in
-column 8 and followed by a period.
-
-@item
-In Erlang code, the tags are the functions, records, and macros defined
-in the file.
-
-@item
-In Fortran code, functions, subroutines and blockdata are tags.
-
-@item
-In makefiles, targets are tags.
-
-@item
-In Objective C code, tags include Objective C definitions for classes,
-class categories, methods, and protocols.
-
-@item
-In Pascal code, the tags are the functions and procedures defined in
-the file.
-
-@item
-In Perl code, the tags are the procedures defined by the @code{sub},
-@code{my} and @code{local} keywords. Use @samp{--globals} if you want
-to tag global variables.
-
-@item
-In PostScript code, the tags are the functions.
-
-@item
-In Prolog code, a tag name appears at the left margin.
-
-@item
-In Python code, @code{def} or @code{class} at the beginning of a line
-generate a tag.
-@end itemize
-
- You can also generate tags based on regexp matching (@pxref{Etags
-Regexps}) to handle other formats and languages.
-
-@node Create Tags Table
-@subsection Creating Tags Tables
-@cindex @code{etags} program
-
- The @code{etags} program is used to create a tags table file. It knows
-the syntax of several languages, as described in
-@iftex
-the previous section.
-@end iftex
-@ifinfo
-@ref{Tag Syntax}.
-@end ifinfo
-Here is how to run @code{etags}:
-
-@example
-etags @var{inputfiles}@dots{}
-@end example
-
-@noindent
-The @code{etags} program reads the specified files, and writes a tags
-table named @file{TAGS} in the current working directory.
-
- If the specified files don't exist, @code{etags} looks for
-compressed versions of them and uncompresses them to read them. Under
-MS-DOS, @code{etags} also looks for file names like @file{mycode.cgz}
-if it is given @samp{mycode.c} on the command line and @file{mycode.c}
-does not exist.
-
- @code{etags} recognizes the language used in an input file based on
-its file name and contents. You can specify the language with the
-@samp{--language=@var{name}} option, described below.
-
- If the tags table data become outdated due to changes in the files
-described in the table, the way to update the tags table is the same
-way it was made in the first place. But it is not necessary to do
-this very often.
-
- If the tags table fails to record a tag, or records it for the wrong
-file, then Emacs cannot possibly find its definition. However, if the
-position recorded in the tags table becomes a little bit wrong (due to
-some editing in the file that the tag definition is in), the only
-consequence is a slight delay in finding the tag. Even if the stored
-position is very wrong, Emacs will still find the tag, but it must
-search the entire file for it.
-
- So you should update a tags table when you define new tags that you want
-to have listed, or when you move tag definitions from one file to another,
-or when changes become substantial. Normally there is no need to update
-the tags table after each edit, or even every day.
-
- One tags table can virtually include another. Specify the included
-tags file name with the @samp{--include=@var{file}} option when
-creating the file that is to include it. The latter file then acts as
-if it covered all the source files specified in the included file, as
-well as the files it directly contains.
-
- If you specify the source files with relative file names when you run
-@code{etags}, the tags file will contain file names relative to the
-directory where the tags file was initially written. This way, you can
-move an entire directory tree containing both the tags file and the
-source files, and the tags file will still refer correctly to the source
-files.
-
- If you specify absolute file names as arguments to @code{etags}, then
-the tags file will contain absolute file names. This way, the tags file
-will still refer to the same files even if you move it, as long as the
-source files remain in the same place. Absolute file names start with
-@samp{/}, or with @samp{@var{device}:/} on MS-DOS and MS-Windows.
-
- When you want to make a tags table from a great number of files, you
-may have problems listing them on the command line, because some systems
-have a limit on its length. The simplest way to circumvent this limit
-is to tell @code{etags} to read the file names from its standard input,
-by typing a dash in place of the file names, like this:
-
-@smallexample
-find . -name "*.[chCH]" -print | etags -
-@end smallexample
-
- Use the option @samp{--language=@var{name}} to specify the language
-explicitly. You can intermix these options with file names; each one
-applies to the file names that follow it. Specify
-@samp{--language=auto} to tell @code{etags} to resume guessing the
-language from the file names and file contents. Specify
-@samp{--language=none} to turn off language-specific processing
-entirely; then @code{etags} recognizes tags by regexp matching alone
-(@pxref{Etags Regexps}).
-
- @samp{etags --help} prints the list of the languages @code{etags}
-knows, and the file name rules for guessing the language. It also prints
-a list of all the available @code{etags} options, together with a short
-explanation.
-
-@node Etags Regexps
-@subsection Etags Regexps
-
- The @samp{--regex} option provides a general way of recognizing tags
-based on regexp matching. You can freely intermix it with file names.
-Each @samp{--regex} option adds to the preceding ones, and applies only
-to the following files. The syntax is:
-
-@smallexample
---regex=/@var{tagregexp}[/@var{nameregexp}]/
-@end smallexample
-
-@noindent
-where @var{tagregexp} is used to match the lines to tag. It is always
-anchored, that is, it behaves as if preceded by @samp{^}. If you want
-to account for indentation, just match any initial number of blanks by
-beginning your regular expression with @samp{[ \t]*}. In the regular
-expressions, @samp{\} quotes the next character, and @samp{\t} stands
-for the tab character. Note that @code{etags} does not handle the other
-C escape sequences for special characters.
-
-@cindex interval operator (in regexps)
- The syntax of regular expressions in @code{etags} is the same as in
-Emacs, augmented with the @dfn{interval operator}, which works as in
-@code{grep} and @code{ed}. The syntax of an interval operator is
-@samp{\@{@var{m},@var{n}\@}}, and its meaning is to match the preceding
-expression at least @var{m} times and up to @var{n} times.
-
- You should not match more characters with @var{tagregexp} than that
-needed to recognize what you want to tag. If the match is such that
-more characters than needed are unavoidably matched by @var{tagregexp}
-(as will usually be the case), you should add a @var{nameregexp}, to
-pick out just the tag. This will enable Emacs to find tags more
-accurately and to do completion on tag names more reliably. You can
-find some examples below.
-
- The option @samp{--ignore-case-regex} (or @samp{-c}) works like
-@samp{--regex}, except that matching ignores case. This is
-appropriate for certain programming languages.
-
- The @samp{-R} option deletes all the regexps defined with
-@samp{--regex} options. It applies to the file names following it, as
-you can see from the following example:
-
-@smallexample
-etags --regex=/@var{reg1}/ voo.doo --regex=/@var{reg2}/ \
- bar.ber -R --lang=lisp los.er
-@end smallexample
-
-@noindent
-Here @code{etags} chooses the parsing language for @file{voo.doo} and
-@file{bar.ber} according to their contents. @code{etags} also uses
-@var{reg1} to recognize additional tags in @file{voo.doo}, and both
-@var{reg1} and @var{reg2} to recognize additional tags in
-@file{bar.ber}. @code{etags} uses the Lisp tags rules, and no regexp
-matching, to recognize tags in @file{los.er}.
-
- You can specify a regular expression for a particular language, by
-writing @samp{@{lang@}} in front of it. Then @code{etags} will use
-the regular expression only for files of that language. (@samp{etags
---help} prints the list of languages recognised by @code{etags}.) The
-following example tags the @code{DEFVAR} macros in the Emacs source
-files, for the C language only:
-
-@smallexample
---regex='@{c@}/[ \t]*DEFVAR_[A-Z_ \t(]+"\([^"]+\)"/'
-@end smallexample
-
-@noindent
-This feature is particularly useful when you store a list of regular
-expressions in a file. The following option syntax instructs
-@code{etags} to read two files of regular expressions. The regular
-expressions contained in the second file are matched without regard to
-case.
-
-@smallexample
---regex=@@first-file --ignore-case-regex=@@second-file
-@end smallexample
-
-@noindent
-A regex file contains one regular expressions per line. Empty lines,
-and lines beginning with space or tab are ignored. When the first
-character in a line is @samp{@@}, @code{etags} assumes that the rest
-of the line is the name of a file of regular expressions; thus, one
-such file can include another file. All the other lines are taken to
-be regular expressions. If the first non-whitespace text on the line
-is @samp{--}, that line is a comment.
-
- For example, one can create a file called @samp{emacs.tags} with the
-following contents:
-
-@smallexample
- -- This is for GNU Emacs C source files
-@{c@}/[ \t]*DEFVAR_[A-Z_ \t(]+"\([^"]+\)"/\1/
-@end smallexample
-
-@noindent
-and then use it like this:
-
-@smallexample
-etags --regex=@@emacs.tags *.[ch] */*.[ch]
-@end smallexample
-
- Here are some more examples. The regexps are quoted to protect them
-from shell interpretation.
-
-@itemize @bullet
-
-@item
-Tag Octave files:
-
-@smallexample
-etags --language=none \
- --regex='/[ \t]*function.*=[ \t]*\([^ \t]*\)[ \t]*(/\1/' \
- --regex='/###key \(.*\)/\1/' \
- --regex='/[ \t]*global[ \t].*/' \
- *.m
-@end smallexample
-
-@noindent
-Note that tags are not generated for scripts, so that you have to add
-a line by yourself of the form @samp{###key @var{scriptname}} if you
-want to jump to it.
-
-@item
-Tag Tcl files:
-
-@smallexample
-etags --language=none --regex='/proc[ \t]+\([^ \t]+\)/\1/' *.tcl
-@end smallexample
-
-@item
-Tag VHDL files:
-
-@smallexample
-etags --language=none \
- --regex='/[ \t]*\(ARCHITECTURE\|CONFIGURATION\) +[^ ]* +OF/' \
- --regex='/[ \t]*\(ATTRIBUTE\|ENTITY\|FUNCTION\|PACKAGE\
- \( BODY\)?\|PROCEDURE\|PROCESS\|TYPE\)[ \t]+\([^ \t(]+\)/\3/'
-@end smallexample
-@end itemize
-
-@node Select Tags Table
-@subsection Selecting a Tags Table
-
-@vindex tags-file-name
-@findex visit-tags-table
- Emacs has at any time one @dfn{selected} tags table, and all the commands
-for working with tags tables use the selected one. To select a tags table,
-type @kbd{M-x visit-tags-table}, which reads the tags table file name as an
-argument. The name @file{TAGS} in the default directory is used as the
-default file name.
-
- All this command does is store the file name in the variable
-@code{tags-file-name}. Emacs does not actually read in the tags table
-contents until you try to use them. Setting this variable yourself is just
-as good as using @code{visit-tags-table}. The variable's initial value is
-@code{nil}; that value tells all the commands for working with tags tables
-that they must ask for a tags table file name to use.
-
- Using @code{visit-tags-table} when a tags table is already loaded
-gives you a choice: you can add the new tags table to the current list
-of tags tables, or start a new list. The tags commands use all the tags
-tables in the current list. If you start a new list, the new tags table
-is used @emph{instead} of others. If you add the new table to the
-current list, it is used @emph{as well as} the others. When the tags
-commands scan the list of tags tables, they don't always start at the
-beginning of the list; they start with the first tags table (if any)
-that describes the current file, proceed from there to the end of the
-list, and then scan from the beginning of the list until they have
-covered all the tables in the list.
-
-@vindex tags-table-list
- You can specify a precise list of tags tables by setting the variable
-@code{tags-table-list} to a list of strings, like this:
-
-@c keep this on two lines for formatting in smallbook
-@example
-@group
-(setq tags-table-list
- '("~/emacs" "/usr/local/lib/emacs/src"))
-@end group
-@end example
-
-@noindent
-This tells the tags commands to look at the @file{TAGS} files in your
-@file{~/emacs} directory and in the @file{/usr/local/lib/emacs/src}
-directory. The order depends on which file you are in and which tags
-table mentions that file, as explained above.
-
- Do not set both @code{tags-file-name} and @code{tags-table-list}.
-
-@node Find Tag
-@subsection Finding a Tag
-
- The most important thing that a tags table enables you to do is to find
-the definition of a specific tag.
-
-@table @kbd
-@item M-.@: @var{tag} @key{RET}
-Find first definition of @var{tag} (@code{find-tag}).
-@item C-u M-.
-Find next alternate definition of last tag specified.
-@item C-u - M-.
-Go back to previous tag found.
-@item C-M-. @var{pattern} @key{RET}
-Find a tag whose name matches @var{pattern} (@code{find-tag-regexp}).
-@item C-u C-M-.
-Find the next tag whose name matches the last pattern used.
-@item C-x 4 .@: @var{tag} @key{RET}
-Find first definition of @var{tag}, but display it in another window
-(@code{find-tag-other-window}).
-@item C-x 5 .@: @var{tag} @key{RET}
-Find first definition of @var{tag}, and create a new frame to select the
-buffer (@code{find-tag-other-frame}).
-@item M-*
-Pop back to where you previously invoked @kbd{M-.} and friends.
-@end table
-
-@kindex M-.
-@findex find-tag
- @kbd{M-.}@: (@code{find-tag}) is the command to find the definition of
-a specified tag. It searches through the tags table for that tag, as a
-string, and then uses the tags table info to determine the file that the
-definition is in and the approximate character position in the file of
-the definition. Then @code{find-tag} visits that file, moves point to
-the approximate character position, and searches ever-increasing
-distances away to find the tag definition.
-
- If an empty argument is given (just type @key{RET}), the sexp in the
-buffer before or around point is used as the @var{tag} argument.
-@xref{Lists}, for info on sexps.
-
- You don't need to give @kbd{M-.} the full name of the tag; a part
-will do. This is because @kbd{M-.} finds tags in the table which
-contain @var{tag} as a substring. However, it prefers an exact match
-to a substring match. To find other tags that match the same
-substring, give @code{find-tag} a numeric argument, as in @kbd{C-u
-M-.}; this does not read a tag name, but continues searching the tags
-table's text for another tag containing the same substring last used.
-If you have a real @key{META} key, @kbd{M-0 M-.}@: is an easier
-alternative to @kbd{C-u M-.}.
-
-@kindex C-x 4 .
-@findex find-tag-other-window
-@kindex C-x 5 .
-@findex find-tag-other-frame
- Like most commands that can switch buffers, @code{find-tag} has a
-variant that displays the new buffer in another window, and one that
-makes a new frame for it. The former is @kbd{C-x 4 .}, which invokes
-the command @code{find-tag-other-window}. The latter is @kbd{C-x 5 .},
-which invokes @code{find-tag-other-frame}.
-
- To move back to places you've found tags recently, use @kbd{C-u -
-M-.}; more generally, @kbd{M-.} with a negative numeric argument. This
-command can take you to another buffer. @kbd{C-x 4 .} with a negative
-argument finds the previous tag location in another window.
-
-@kindex M-*
-@findex pop-tag-mark
-@vindex find-tag-marker-ring-length
- As well as going back to places you've found tags recently, you can go
-back to places @emph{from where} you found them. Use @kbd{M-*}, which
-invokes the command @code{pop-tag-mark}, for this. Typically you would
-find and study the definition of something with @kbd{M-.} and then
-return to where you were with @kbd{M-*}.
-
- Both @kbd{C-u - M-.} and @kbd{M-*} allow you to retrace your steps to
-a depth determined by the variable @code{find-tag-marker-ring-length}.
-
-@findex find-tag-regexp
-@kindex C-M-.
- The command @kbd{C-M-.} (@code{find-tag-regexp}) visits the tags that
-match a specified regular expression. It is just like @kbd{M-.} except
-that it does regexp matching instead of substring matching.
-
-@node Tags Search
-@subsection Searching and Replacing with Tags Tables
-@cindex search and replace in multiple files
-@cindex multiple-file search and replace
-
- The commands in this section visit and search all the files listed in the
-selected tags table, one by one. For these commands, the tags table serves
-only to specify a sequence of files to search.
-
-@table @kbd
-@item M-x tags-search @key{RET} @var{regexp} @key{RET}
-Search for @var{regexp} through the files in the selected tags
-table.
-@item M-x tags-query-replace @key{RET} @var{regexp} @key{RET} @var{replacement} @key{RET}
-Perform a @code{query-replace-regexp} on each file in the selected tags table.
-@item M-,
-Restart one of the commands above, from the current location of point
-(@code{tags-loop-continue}).
-@end table
-
-@findex tags-search
- @kbd{M-x tags-search} reads a regexp using the minibuffer, then
-searches for matches in all the files in the selected tags table, one
-file at a time. It displays the name of the file being searched so you
-can follow its progress. As soon as it finds an occurrence,
-@code{tags-search} returns.
-
-@kindex M-,
-@findex tags-loop-continue
- Having found one match, you probably want to find all the rest. To find
-one more match, type @kbd{M-,} (@code{tags-loop-continue}) to resume the
-@code{tags-search}. This searches the rest of the current buffer, followed
-by the remaining files of the tags table.@refill
-
-@findex tags-query-replace
- @kbd{M-x tags-query-replace} performs a single
-@code{query-replace-regexp} through all the files in the tags table. It
-reads a regexp to search for and a string to replace with, just like
-ordinary @kbd{M-x query-replace-regexp}. It searches much like @kbd{M-x
-tags-search}, but repeatedly, processing matches according to your
-input. @xref{Replace}, for more information on query replace.
-
-@vindex tags-case-fold-search
-@cindex case-sensitivity and tags search
- You can control the case-sensitivity of tags search commands by
-customizing the value of the variable @code{tags-case-fold-search}. The
-default is to use the same setting as the value of
-@code{case-fold-search} (@pxref{Search Case}).
-
- It is possible to get through all the files in the tags table with a
-single invocation of @kbd{M-x tags-query-replace}. But often it is
-useful to exit temporarily, which you can do with any input event that
-has no special query replace meaning. You can resume the query replace
-subsequently by typing @kbd{M-,}; this command resumes the last tags
-search or replace command that you did.
-
- The commands in this section carry out much broader searches than the
-@code{find-tag} family. The @code{find-tag} commands search only for
-definitions of tags that match your substring or regexp. The commands
-@code{tags-search} and @code{tags-query-replace} find every occurrence
-of the regexp, as ordinary search commands and replace commands do in
-the current buffer.
-
- These commands create buffers only temporarily for the files that they
-have to search (those which are not already visited in Emacs buffers).
-Buffers in which no match is found are quickly killed; the others
-continue to exist.
-
- It may have struck you that @code{tags-search} is a lot like
-@code{grep}. You can also run @code{grep} itself as an inferior of
-Emacs and have Emacs show you the matching lines one by one. This works
-much like running a compilation; finding the source locations of the
-@code{grep} matches works like finding the compilation errors.
-@xref{Compilation}.
-
-@node List Tags
-@subsection Tags Table Inquiries
-
-@table @kbd
-@item M-x list-tags @key{RET} @var{file} @key{RET}
-Display a list of the tags defined in the program file @var{file}.
-@item M-x tags-apropos @key{RET} @var{regexp} @key{RET}
-Display a list of all tags matching @var{regexp}.
-@end table
-
-@findex list-tags
- @kbd{M-x list-tags} reads the name of one of the files described by
-the selected tags table, and displays a list of all the tags defined in
-that file. The ``file name'' argument is really just a string to
-compare against the file names recorded in the tags table; it is read as
-a string rather than as a file name. Therefore, completion and
-defaulting are not available, and you must enter the file name the same
-way it appears in the tags table. Do not include a directory as part of
-the file name unless the file name recorded in the tags table includes a
-directory.
-
-@findex tags-apropos
-@vindex tags-apropos-verbose
- @kbd{M-x tags-apropos} is like @code{apropos} for tags
-(@pxref{Apropos}). It finds all the tags in the selected tags table
-whose entries match @var{regexp}, and displays them. If the variable
-@code{tags-apropos-verbose} is non-@code{nil}, it displays the names
-of the tags files together with the tag names.
-
-@vindex tags-tag-face
-@vindex tags-apropos-additional-actions
-You can customize the appearance of the output with the face
-@code{tags-tag-face}. You can display additional output with @kbd{M-x
-tags-apropos} by customizing the variable
-@code{tags-apropos-additional-actions}---see its documentation for
-details.
-
- You can also use the collection of tag names to complete a symbol
-name in the buffer. @xref{Symbol Completion}.
-
-@node Imenu
-@section Imenu
-@cindex indexes of buffer contents
-@cindex buffer content indexes
-@cindex tags
-
- The Imenu facility is another way to find definitions or sections
-in a file. It is similar in spirit to Tags, but operates on a single
-buffer only, and works entirely within Emacs with no need for a separate
-tags table.
-
-@findex imenu
-@findex imenu-add-menu-bar-index
- If you type @kbd{M-x imenu}, it reads the name of a section or
-definition in the current buffer, then goes to that section or
-definition. You can use completion to specify the name, and a
-complete list of possible names is always displayed.
-
- Alternatively you can bind the command @code{imenu} to a mouse
-click. Then it displays mouse menus for you to select the section or
-definition you want. You can also add the buffer's index to the menu
-bar by calling @code{imenu-add-menu-bar-index}. If you want to have
-this menu bar item available for all buffers in a certain major mode,
-you can do this by adding @code{imenu-add-menu-bar-index} to its mode
-hook. But then you will have to wait for the buffer to be searched
-for sections and definitions, each time you visit a file which uses
-that mode.
-
-@vindex imenu-auto-rescan
- When you change the contents of a buffer, if you add or delete
-definitions or sections, you can update the buffer's index to
-correspond to the new contents by invoking the @samp{*Rescan*} item in
-the menu. Rescanning happens automatically if
-@code{imenu-auto-rescan} is non-@code{nil}. There is no need to
-rescan because of small changes in the text.
-
-@vindex imenu-sort-function
- You can customize the way the menus are sorted via the variable
-@code{imenu-sort-function}. By default names are ordered as they
-occur in the buffer; alphabetic sorting is provided as an alternative.
-
- Imenu provides the information to guide Which Function mode
-(@pxref{Which Function}). The Speedbar can also use it
-(@pxref{Speedbar}).
-
-@node Emerge, C Modes, Imenu, Programs
-@section Merging Files with Emerge
-@cindex Emerge
-@cindex merging files
-
-It's not unusual for programmers to get their signals crossed and modify
-the same program in two different directions. To recover from this
-confusion, you need to merge the two versions. Emerge makes this
-easier. See also @ref{Comparing Files}, for commands to compare
-in a more manual fashion, and @ref{,Ediff,, ediff, The Ediff Manual}.
-
-@menu
-* Overview of Emerge:: How to start Emerge. Basic concepts.
-* Submodes of Emerge:: Fast mode vs. Edit mode.
- Skip Prefers mode and Auto Advance mode.
-* State of Difference:: You do the merge by specifying state A or B
- for each difference.
-* Merge Commands:: Commands for selecting a difference,
- changing states of differences, etc.
-* Exiting Emerge:: What to do when you've finished the merge.
-* Combining in Emerge:: How to keep both alternatives for a difference.
-* Fine Points of Emerge:: Misc.
-@end menu
-
-@node Overview of Emerge
-@subsection Overview of Emerge
-
-To start Emerge, run one of these four commands:
-
-@table @kbd
-@item M-x emerge-files
-@findex emerge-files
-Merge two specified files.
-
-@item M-x emerge-files-with-ancestor
-@findex emerge-files-with-ancestor
-Merge two specified files, with reference to a common ancestor.
-
-@item M-x emerge-buffers
-@findex emerge-buffers
-Merge two buffers.
-
-@item M-x emerge-buffers-with-ancestor
-@findex emerge-buffers-with-ancestor
-Merge two buffers with reference to a common ancestor in a third
-buffer.
-@end table
-
-@cindex merge buffer (Emerge)
-@cindex A and B buffers (Emerge)
- The Emerge commands compare two files or buffers, and display the
-comparison in three buffers: one for each input text (the @dfn{A buffer}
-and the @dfn{B buffer}), and one (the @dfn{merge buffer}) where merging
-takes place. The merge buffer shows the full merged text, not just the
-differences. Wherever the two input texts differ, you can choose which
-one of them to include in the merge buffer.
-
- The Emerge commands that take input from existing buffers use only the
-accessible portions of those buffers, if they are narrowed
-(@pxref{Narrowing}).
-
- If a common ancestor version is available, from which the two texts to
-be merged were both derived, Emerge can use it to guess which
-alternative is right. Wherever one current version agrees with the
-ancestor, Emerge presumes that the other current version is a deliberate
-change which should be kept in the merged version. Use the
-@samp{with-ancestor} commands if you want to specify a common ancestor
-text. These commands read three file or buffer names---variant A,
-variant B, and the common ancestor.
-
- After the comparison is done and the buffers are prepared, the
-interactive merging starts. You control the merging by typing special
-@dfn{merge commands} in the merge buffer. The merge buffer shows you a
-full merged text, not just differences. For each run of differences
-between the input texts, you can choose which one of them to keep, or
-edit them both together.
-
- The merge buffer uses a special major mode, Emerge mode, with commands
-for making these choices. But you can also edit the buffer with
-ordinary Emacs commands.
-
- At any given time, the attention of Emerge is focused on one
-particular difference, called the @dfn{selected} difference. This
-difference is marked off in the three buffers like this:
-
-@example
-vvvvvvvvvvvvvvvvvvvv
-@var{text that differs}
-^^^^^^^^^^^^^^^^^^^^
-@end example
-
-@noindent
-Emerge numbers all the differences sequentially and the mode
-line always shows the number of the selected difference.
-
- Normally, the merge buffer starts out with the A version of the text.
-But when the A version of a difference agrees with the common ancestor,
-then the B version is initially preferred for that difference.
-
- Emerge leaves the merged text in the merge buffer when you exit. At
-that point, you can save it in a file with @kbd{C-x C-w}. If you give a
-numeric argument to @code{emerge-files} or
-@code{emerge-files-with-ancestor}, it reads the name of the output file
-using the minibuffer. (This is the last file name those commands read.)
-Then exiting from Emerge saves the merged text in the output file.
-
- Normally, Emerge commands save the output buffer in its file when you
-exit. If you abort Emerge with @kbd{C-]}, the Emerge command does not
-save the output buffer, but you can save it yourself if you wish.
-
-@node Submodes of Emerge
-@subsection Submodes of Emerge
-
- You can choose between two modes for giving merge commands: Fast mode
-and Edit mode. In Fast mode, basic merge commands are single
-characters, but ordinary Emacs commands are disabled. This is
-convenient if you use only merge commands. In Edit mode, all merge
-commands start with the prefix key @kbd{C-c C-c}, and the normal Emacs
-commands are also available. This allows editing the merge buffer, but
-slows down Emerge operations.
-
- Use @kbd{e} to switch to Edit mode, and @kbd{C-c C-c f} to switch to
-Fast mode. The mode line indicates Edit and Fast modes with @samp{E}
-and @samp{F}.
-
- Emerge has two additional submodes that affect how particular merge
-commands work: Auto Advance mode and Skip Prefers mode.
-
- If Auto Advance mode is in effect, the @kbd{a} and @kbd{b} commands
-advance to the next difference. This lets you go through the merge
-faster as long as you simply choose one of the alternatives from the
-input. The mode line indicates Auto Advance mode with @samp{A}.
-
- If Skip Prefers mode is in effect, the @kbd{n} and @kbd{p} commands
-skip over differences in states prefer-A and prefer-B (@pxref{State of
-Difference}). Thus you see only differences for which neither version
-is presumed ``correct.'' The mode line indicates Skip Prefers mode with
-@samp{S}.
-
-@findex emerge-auto-advance-mode
-@findex emerge-skip-prefers-mode
- Use the command @kbd{s a} (@code{emerge-auto-advance-mode}) to set or
-clear Auto Advance mode. Use @kbd{s s}
-(@code{emerge-skip-prefers-mode}) to set or clear Skip Prefers mode.
-These commands turn on the mode with a positive argument, turns it off
-with a negative or zero argument, and toggle the mode with no argument.
-
-@node State of Difference
-@subsection State of a Difference
-
- In the merge buffer, a difference is marked with lines of @samp{v} and
-@samp{^} characters. Each difference has one of these seven states:
-
-@table @asis
-@item A
-The difference is showing the A version. The @kbd{a} command always
-produces this state; the mode line indicates it with @samp{A}.
-
-@item B
-The difference is showing the B version. The @kbd{b} command always
-produces this state; the mode line indicates it with @samp{B}.
-
-@item default-A
-@itemx default-B
-The difference is showing the A or the B state by default, because you
-haven't made a choice. All differences start in the default-A state
-(and thus the merge buffer is a copy of the A buffer), except those for
-which one alternative is ``preferred'' (see below).
-
-When you select a difference, its state changes from default-A or
-default-B to plain A or B. Thus, the selected difference never has
-state default-A or default-B, and these states are never displayed in
-the mode line.
-
-The command @kbd{d a} chooses default-A as the default state, and @kbd{d
-b} chooses default-B. This chosen default applies to all differences
-which you haven't ever selected and for which no alternative is preferred.
-If you are moving through the merge sequentially, the differences you
-haven't selected are those following the selected one. Thus, while
-moving sequentially, you can effectively make the A version the default
-for some sections of the merge buffer and the B version the default for
-others by using @kbd{d a} and @kbd{d b} between sections.
-
-@item prefer-A
-@itemx prefer-B
-The difference is showing the A or B state because it is
-@dfn{preferred}. This means that you haven't made an explicit choice,
-but one alternative seems likely to be right because the other
-alternative agrees with the common ancestor. Thus, where the A buffer
-agrees with the common ancestor, the B version is preferred, because
-chances are it is the one that was actually changed.
-
-These two states are displayed in the mode line as @samp{A*} and @samp{B*}.
-
-@item combined
-The difference is showing a combination of the A and B states, as a
-result of the @kbd{x c} or @kbd{x C} commands.
-
-Once a difference is in this state, the @kbd{a} and @kbd{b} commands
-don't do anything to it unless you give them a numeric argument.
-
-The mode line displays this state as @samp{comb}.
-@end table
-
-@node Merge Commands
-@subsection Merge Commands
-
- Here are the Merge commands for Fast mode; in Edit mode, precede them
-with @kbd{C-c C-c}:
-
-@table @kbd
-@item p
-Select the previous difference.
-
-@item n
-Select the next difference.
+than the comment starting delimiter in the strictest sense of the word;
+for example, in C mode the value of the variable is
+@c This stops M-q from breaking the line inside that @code.
+@code{@w{"/\\*+ *\\|//+ *"}}, which matches extra stars and spaces
+after the @samp{/*} itself, and accepts C++ style comments also.
+(Note that @samp{\\} is needed in Lisp syntax to include a @samp{\} in
+the string, which is needed to deny the first star its special meaning
+in regexp syntax. @xref{Regexp Backslash}.)
-@item a
-Choose the A version of this difference.
+@vindex comment-start
+@vindex comment-end
+ When a comment command makes a new comment, it inserts the value of
+@code{comment-start} to begin it. The value of @code{comment-end} is
+inserted after point, so that it will follow the text that you will
+insert into the comment. When @code{comment-end} is non-empty, it
+should start with a space. For example, in C mode,
+@code{comment-start} has the value @w{@code{"/* "}} and
+@code{comment-end} has the value @w{@code{" */"}}.
-@item b
-Choose the B version of this difference.
+@vindex comment-padding
+ The variable @code{comment-padding} specifies how many spaces
+@code{comment-region} should insert on each line between the comment
+delimiter and the line's original text. The default is 1, to insert
+one space. @code{nil} means 0. Alternatively, @code{comment-padding}
+can hold the actual string to insert.
-@item C-u @var{n} j
-Select difference number @var{n}.
+@vindex comment-multi-line
+ The variable @code{comment-multi-line} controls how @kbd{C-M-j}
+(@code{indent-new-comment-line}) behaves when used inside a comment.
+Specifically, when @code{comment-multi-line} is @code{nil}, the
+command inserts a comment terminator, begins a new line, and finally
+inserts a comment starter. Otherwise it does not insert the
+terminator and starter, so it effectively continues the current
+comment across multiple lines. In languages that allow multi-line
+comments, the choice of value for this variable is a matter of taste.
+The default for this variable depends on the major mode.
-@item .
-Select the difference containing point. You can use this command in the
-merge buffer or in the A or B buffer.
+@vindex comment-indent-function
+ The variable @code{comment-indent-function} should contain a function
+that will be called to compute the alignment for a newly inserted
+comment or for aligning an existing comment. It is set differently by
+various major modes. The function is called with no arguments, but with
+point at the beginning of the comment, or at the end of a line if a new
+comment is to be inserted. It should return the column in which the
+comment ought to start. For example, in Lisp mode, the indent hook
+function bases its decision on how many semicolons begin an existing
+comment, and on the code in the preceding lines.
-@item q
-Quit---finish the merge.
+@node Documentation
+@section Documentation Lookup
-@item C-]
-Abort---exit merging and do not save the output.
+ Emacs provides several features you can use to look up the
+documentation of functions, variables and commands that you plan to
+use in your program.
-@item f
-Go into Fast mode. (In Edit mode, this is actually @kbd{C-c C-c f}.)
+@menu
+* Info Lookup:: Looking up library functions and commands
+ in Info files.
+* Man Page:: Looking up man pages of library functions and commands.
+* Lisp Doc:: Looking up Emacs Lisp functions, etc.
+@end menu
-@item e
-Go into Edit mode.
+@node Info Lookup
+@subsection Info Documentation Lookup
-@item l
-Recenter (like @kbd{C-l}) all three windows.
+@findex info-lookup-symbol
+@findex info-lookup-file
+@kindex C-h S
+ For many major modes, that apply to languages that have
+documentation in Info, you can use @kbd{C-h S}
+(@code{info-lookup-symbol}) to view the Info documentation for a
+symbol used in the program. You specify the symbol with the
+minibuffer; the default is the symbol appearing in the buffer at
+point. For example, in C mode this looks for the symbol in the C
+Library Manual. The command only works if the appropriate manual's
+Info files are installed.
+
+ The major mode determines where to look for documentation for the
+symbol---which Info files to look in, and which indices to search.
+You can also use @kbd{M-x info-lookup-file} to look for documentation
+for a file name.
+
+ If you use @kbd{C-h S} in a major mode that does not support it,
+it asks you to specify the ``symbol help mode''. You should enter
+a command such as @code{c-mode} that would select a major
+mode which @kbd{C-h S} does support.
+
+@node Man Page
+@subsection Man Page Lookup
+
+@cindex manual page
+ On Unix, the main form of on-line documentation was the @dfn{manual
+page} or @dfn{man page}. In the GNU operating system, we aim to
+replace man pages with better-organized manuals that you can browse
+with Info (@pxref{Misc Help}). This process is not finished, so it is
+still useful to read manual pages.
-@item -
-Specify part of a prefix numeric argument.
+@findex manual-entry
+ You can read the man page for an operating system command, library
+function, or system call, with the @kbd{M-x man} command. It
+runs the @code{man} program to format the man page; if the system
+permits, it runs @code{man} asynchronously, so that you can keep on
+editing while the page is being formatted. (On MS-DOS and MS-Windows
+3, you cannot edit while Emacs waits for @code{man} to finish.) The
+result goes in a buffer named @samp{*Man @var{topic}*}. These buffers
+use a special major mode, Man mode, that facilitates scrolling and
+jumping to other manual pages. For details, type @kbd{C-h m} while in
+a man page buffer.
-@item @var{digit}
-Also specify part of a prefix numeric argument.
+@cindex sections of manual pages
+ Each man page belongs to one of ten or more @dfn{sections}, each
+named by a digit or by a digit and a letter. Sometimes there are
+multiple man pages with the same name in different sections. To read
+a man page from a specific section, type
+@samp{@var{topic}(@var{section})} or @samp{@var{section} @var{topic}}
+when @kbd{M-x manual-entry} prompts for the topic. For example, to
+read the man page for the C library function @code{chmod} (as opposed
+to a command of the same name), type @kbd{M-x manual-entry @key{RET}
+chmod(2) @key{RET}}. (@code{chmod} is a system call, so it is in
+section @samp{2}.)
+
+@vindex Man-switches
+ If you do not specify a section, the results depend on how the
+@code{man} program works on your system. Some of them display only
+the first man page they find. Others display all man pages that have
+the specified name, so you can move between them with the @kbd{M-n}
+and @kbd{M-p} keys@footnote{On some systems, the @code{man} program
+accepts a @samp{-a} command-line option which tells it to display all
+the man pages for the specified topic. If you want this behavior, you
+can add this option to the value of the variable @code{Man-switches}.}.
+The mode line shows how many manual pages are present in the Man buffer.
-@item d a
-Choose the A version as the default from here down in
-the merge buffer.
+@vindex Man-fontify-manpage-flag
+ By default, Emacs highlights the text in man pages. For a long man
+page, highlighting can take substantial time. You can turn off
+highlighting of man pages by setting the variable
+@code{Man-fontify-manpage-flag} to @code{nil}.
-@item d b
-Choose the B version as the default from here down in
-the merge buffer.
+@findex Man-fontify-manpage
+ If you insert the text of a man page into an Emacs buffer in some
+other fashion, you can use the command @kbd{M-x Man-fontify-manpage} to
+perform the same conversions that @kbd{M-x manual-entry} does.
-@item c a
-Copy the A version of this difference into the kill ring.
+@findex woman
+@cindex manual pages, on MS-DOS/MS-Windows
+ An alternative way of reading manual pages is the @kbd{M-x woman}
+command@footnote{The name of the command, @code{woman}, is an acronym
+for ``w/o (without) man,'' since it doesn't use the @code{man}
+program.}. Unlike @kbd{M-x man}, it does not run any external
+programs to format and display the man pages; instead it does the job
+in Emacs Lisp, so it works on systems such as MS-Windows, where the
+@code{man} program (and other programs it uses) are not generally
+available.
-@item c b
-Copy the B version of this difference into the kill ring.
+ @kbd{M-x woman} prompts for a name of a manual page, and provides
+completion based on the list of manual pages that are installed on
+your machine; the list of available manual pages is computed
+automatically the first time you invoke @code{woman}. The word at
+point in the current buffer is used to suggest the default for the
+name the manual page.
-@item i a
-Insert the A version of this difference at point.
+ With a numeric argument, @kbd{M-x woman} recomputes the list of the
+manual pages used for completion. This is useful if you add or delete
+manual pages.
-@item i b
-Insert the B version of this difference at point.
+ If you type a name of a manual page and @kbd{M-x woman} finds that
+several manual pages by the same name exist in different sections, it
+pops up a window with possible candidates asking you to choose one of
+them.
-@item m
-Put point and mark around the difference.
+ For more information about setting up and using @kbd{M-x woman}, see
+@ref{Top, WoMan, Browse UN*X Manual Pages WithOut Man, woman, The WoMan
+Manual}.
-@item ^
-Scroll all three windows down (like @kbd{M-v}).
+@node Lisp Doc
+@subsection Emacs Lisp Documentation Lookup
-@item v
-Scroll all three windows up (like @kbd{C-v}).
+ As you edit Lisp code to be run in Emacs, you can use the commands
+@kbd{C-h f} (@code{describe-function}) and @kbd{C-h v}
+(@code{describe-variable}) to view documentation of functions and
+variables that you want to use. These commands use the minibuffer to
+read the name of a function or variable to document, and display the
+documentation in a window. Their default arguments are based on the
+code in the neighborhood of point. For @kbd{C-h f}, the default is
+the function called in the innermost list containing point. @kbd{C-h
+v} uses the symbol name around or adjacent to point as its default.
-@item <
-Scroll all three windows left (like @kbd{C-x <}).
+@cindex Eldoc mode
+@findex eldoc-mode
+ A more automatic but less powerful method is Eldoc mode. This minor
+mode constantly displays in the echo area the argument list for the
+function being called at point. (In other words, it finds the
+function call that point is contained in, and displays the argument
+list of that function.) If point is over a documented variable, it
+shows the first line of the variable's docstring. Eldoc mode applies
+in Emacs Lisp and Lisp Interaction modes, and perhaps a few others
+that provide special support for looking up doc strings. Use the
+command @kbd{M-x eldoc-mode} to enable or disable this feature.
-@item >
-Scroll all three windows right (like @kbd{C-x >}).
+@node Hideshow
+@section Hideshow minor mode
-@item |
-Reset horizontal scroll on all three windows.
+@findex hs-minor-mode
+ Hideshow minor mode provides selective display of portions of a
+program, known as @dfn{blocks}. You can use @kbd{M-x hs-minor-mode}
+to enable or disable this mode, or add @code{hs-minor-mode} to the
+mode hook for certain major modes in order to enable it automatically
+for those modes.
-@item x 1
-Shrink the merge window to one line. (Use @kbd{C-u l} to restore it
-to full size.)
+ Just what constitutes a block depends on the major mode. In C mode
+or C++ mode, they are delimited by braces, while in Lisp mode and
+similar modes they are delimited by parentheses. Multi-line comments
+also count as blocks.
-@item x c
-Combine the two versions of this difference (@pxref{Combining in
-Emerge}).
+@findex hs-hide-all
+@findex hs-hide-block
+@findex hs-show-all
+@findex hs-show-block
+@findex hs-show-region
+@findex hs-hide-level
+@findex hs-minor-mode
+@kindex C-c @@ C-h
+@kindex C-c @@ C-s
+@kindex C-c @@ C-M-h
+@kindex C-c @@ C-M-s
+@kindex C-c @@ C-r
+@kindex C-c @@ C-l
+@kindex S-Mouse-2
+@table @kbd
+@item C-c @@ C-h
+Hide the current block (@code{hs-hide-block}).
+@item C-c @@ C-s
+Show the current block (@code{hs-show-block}).
+@item C-c @@ C-c
+Either hide or show the current block (@code{hs-toggle-hiding}).
+@item S-Mouse-2
+Either hide or show the block you click on (@code{hs-mouse-toggle-hiding}).
+@item C-c @@ C-M-h
+Hide all top-level blocks (@code{hs-hide-all}).
+@item C-c @@ C-M-s
+Show everything in the buffer (@code{hs-show-all}).
+@item C-c @@ C-l
+Hide all blocks @var{n} levels below this block
+(@code{hs-hide-level}).
+@end table
-@item x f
-Show the names of the files/buffers Emerge is operating on, in a Help
-window. (Use @kbd{C-u l} to restore windows.)
+@vindex hs-hide-comments-when-hiding-all
+@vindex hs-isearch-open
+@vindex hs-special-modes-alist
+ These variables exist for customizing Hideshow mode.
-@item x j
-Join this difference with the following one.
-(@kbd{C-u x j} joins this difference with the previous one.)
+@table @code
+@item hs-hide-comments-when-hiding-all
+Non-@code{nil} says that @kbd{hs-hide-all} should hide comments too.
-@item x s
-Split this difference into two differences. Before you use this
-command, position point in each of the three buffers at the place where
-you want to split the difference.
+@item hs-isearch-open
+Specifies what kind of hidden blocks incremental search should make
+visible. The value should be one of these four symbols:
-@item x t
-Trim identical lines off the top and bottom of the difference.
-Such lines occur when the A and B versions are
-identical but differ from the ancestor version.
+@table @code
+@item code
+Open only code blocks.
+@item comment
+Open only comments.
+@item t
+Open both code blocks and comments.
+@item nil
+Open neither code blocks nor comments.
@end table
-@node Exiting Emerge
-@subsection Exiting Emerge
-
- The @kbd{q} command (@code{emerge-quit}) finishes the merge, storing
-the results into the output file if you specified one. It restores the
-A and B buffers to their proper contents, or kills them if they were
-created by Emerge and you haven't changed them. It also disables the
-Emerge commands in the merge buffer, since executing them later could
-damage the contents of the various buffers.
-
- @kbd{C-]} aborts the merge. This means exiting without writing the
-output file. If you didn't specify an output file, then there is no
-real difference between aborting and finishing the merge.
-
- If the Emerge command was called from another Lisp program, then its
-return value is @code{t} for successful completion, or @code{nil} if you
-abort.
+@item hs-special-modes-alist
+A list of elements, each specifying how to initialize Hideshow
+variables for one major mode. See the variable's documentation string
+for more information.
+@end table
-@node Combining in Emerge
-@subsection Combining the Two Versions
+@node Symbol Completion
+@section Completion for Symbol Names
+@cindex completion (symbol names)
- Sometimes you want to keep @emph{both} alternatives for a particular
-difference. To do this, use @kbd{x c}, which edits the merge buffer
-like this:
+ In Emacs, completion is something you normally do in the minibuffer.
+But one kind of completion is available in all buffers: completion for
+symbol names.
-@example
-@group
-#ifdef NEW
-@var{version from A buffer}
-#else /* not NEW */
-@var{version from B buffer}
-#endif /* not NEW */
-@end group
-@end example
+@kindex M-TAB
+ The character @kbd{M-@key{TAB}} runs a command to complete the
+partial symbol before point against the set of meaningful symbol
+names. This command inserts at point any additional characters that
+it can determine from the partial name. (If your window manager
+defines @kbd{M-@key{TAB}} to switch windows, you can type
+@kbd{@key{ESC} @key{TAB}} or @kbd{C-M-i}.)
+
+ If the partial name in the buffer has multiple possible completions
+that differ in the very next character, so that it is impossible to
+complete even one more character, @kbd{M-@key{TAB}} displays a list of
+all possible completions in another window.
-@noindent
-@vindex emerge-combine-versions-template
-While this example shows C preprocessor conditionals delimiting the two
-alternative versions, you can specify the strings to use by setting
-the variable @code{emerge-combine-versions-template} to a string of your
-choice. In the string, @samp{%a} says where to put version A, and
-@samp{%b} says where to put version B. The default setting, which
-produces the results shown above, looks like this:
+@cindex tags-based completion
+@cindex Info index completion
+@findex complete-symbol
+ In most programming language major modes, @kbd{M-@key{TAB}} runs the
+command @code{complete-symbol}, which provides two kinds of completion.
+Normally it does completion based on a tags table (@pxref{Tags}); with a
+numeric argument (regardless of the value), it does completion based on
+the names listed in the Info file indexes for your language. Thus, to
+complete the name of a symbol defined in your own program, use
+@kbd{M-@key{TAB}} with no argument; to complete the name of a standard
+library function, use @kbd{C-u M-@key{TAB}}. Of course, Info-based
+completion works only if there is an Info file for the standard library
+functions of your language, and only if it is installed at your site.
-@example
-@group
-"#ifdef NEW\n%a#else /* not NEW */\n%b#endif /* not NEW */\n"
-@end group
-@end example
+@cindex Lisp symbol completion
+@cindex completion (Lisp symbols)
+@findex lisp-complete-symbol
+ In Emacs-Lisp mode, the name space for completion normally consists of
+nontrivial symbols present in Emacs---those that have function
+definitions, values or properties. However, if there is an
+open-parenthesis immediately before the beginning of the partial symbol,
+only symbols with function definitions are considered as completions.
+The command which implements this is @code{lisp-complete-symbol}.
-@node Fine Points of Emerge
-@subsection Fine Points of Emerge
+ In Text mode and related modes, @kbd{M-@key{TAB}} completes words
+based on the spell-checker's dictionary. @xref{Spelling}.
- During the merge, you mustn't try to edit the A and B buffers yourself.
-Emerge modifies them temporarily, but ultimately puts them back the way
-they were.
+@node Glasses
+@section Glasses minor mode
+@cindex Glasses mode
+@cindex identifiers, making long ones readable
+@cindex StudlyCaps, making them readable
+@findex glasses-mode
- You can have any number of merges going at once---just don't use any one
-buffer as input to more than one merge at once, since the temporary
-changes made in these buffers would get in each other's way.
+ Glasses minor mode makes @samp{unreadableIdentifiersLikeThis}
+readable by altering the way they display. It knows two different
+ways to do this: by displaying underscores between a lower-case letter
+and the following capital letter, and by emboldening the capital
+letters. It does not alter the buffer text, only the way they
+display, so you can use it even on read-only buffers. You can use the
+command @kbd{M-x glasses-mode} to enable or disable the mode in the
+current buffer; you can also add @code{glasses-mode} to the mode hook
+of the programming language major modes in which you normally want
+to use Glasses mode.
+
+@node Misc for Programs
+@section Other Features Useful for Editing Programs
+
+ A number of Emacs commands that aren't designed specifically for
+editing programs are useful for that nonetheless.
+
+ The Emacs commands that operate on words, sentences and paragraphs
+are useful for editing code. Most symbols names contain words
+(@pxref{Words}); sentences can be found in strings and comments
+(@pxref{Sentences}). Paragraphs in the strict sense can be found in
+program code (in long comments), but the paragraph commands are useful
+in other places too, because programming language major modes define
+paragraphs to begin and end at blank lines (@pxref{Paragraphs}).
+Judicious use of blank lines to make the program clearer will also
+provide useful chunks of text for the paragraph commands to work on.
+Auto Fill mode, if enabled in a programming language major mode,
+indents the new lines which it creates.
- Starting Emerge can take a long time because it needs to compare the
-files fully. Emacs can't do anything else until @code{diff} finishes.
-Perhaps in the future someone will change Emerge to do the comparison in
-the background when the input files are large---then you could keep on
-doing other things with Emacs until Emerge is ready to accept
-commands.
+ The selective display feature is useful for looking at the overall
+structure of a function (@pxref{Selective Display}). This feature
+hides the lines that are indented more than a specified amount.
+Programming modes often support Outline minor mode (@pxref{Outline
+Mode}). The Foldout package provides folding-editor features
+(@pxref{Foldout}).
-@vindex emerge-startup-hook
- After setting up the merge, Emerge runs the hook
-@code{emerge-startup-hook} (@pxref{Hooks}).
+ The ``automatic typing'' features may be useful for writing programs.
+@xref{Top,,Autotyping, autotype, Autotyping}.
@node C Modes
@section C and Related Modes
@cindex CORBA IDL mode
@cindex Objective C mode
@cindex C++ mode
+@cindex AWK mode
@cindex mode, Java
@cindex mode, C
+@cindex mode, C++
@cindex mode, Objective C
@cindex mode, CORBA IDL
@cindex mode, Pike
+@cindex mode, AWK
This section gives a brief description of the special features
-available in C, C++, Objective-C, Java, CORBA IDL, and Pike modes.
-(These are called ``C mode and related modes.'') @xref{Top, CC Mode,
-ccmode, , CC Mode}, for a more extensive description of these modes
+available in C, C++, Objective-C, Java, CORBA IDL, Pike and AWK modes.
+(These are called ``C mode and related modes.'') @xref{Top, , CC Mode,
+ccmode, CC Mode}, for a more extensive description of these modes
and their special features.
@menu
-* Motion in C::
-* Electric C::
-* Hungry Delete::
-* Other C Commands::
-* Comments in C::
+* Motion in C:: Commands to move by C statements, etc.
+* Electric C:: Colon and other chars can automatically reindent.
+* Hungry Delete:: A more powerful DEL command.
+* Other C Commands:: Filling comments, viewing expansion of macros,
+ and other neat features.
@end menu
@node Motion in C
related modes.
@table @code
+@item M-x c-beginning-of-defun
+@itemx M-x c-end-of-defun
+@findex c-beginning-of-defun
+@findex c-end-of-defun
+Move point to the beginning or end of the current function or
+top-level definition. These are found by searching for the least
+enclosing braces. (By contrast, @code{beginning-of-defun} and
+@code{end-of-defun} search for braces in column zero.) If you are
+editing code where the opening brace of a function isn't placed in
+column zero, you may wish to bind @code{C-M-a} and @code{C-M-e} to
+these commands. @xref{Moving by Defuns}.
+
@item C-c C-u
@kindex C-c C-u @r{(C mode)}
@findex c-up-conditional
Move point back to the containing preprocessor conditional, leaving the
mark behind. A prefix argument acts as a repeat count. With a negative
argument, move point forward to the end of the containing
-preprocessor conditional. When going backwards, @code{#elif} is treated
-like @code{#else} followed by @code{#if}. When going forwards,
-@code{#elif} is ignored.@refill
+preprocessor conditional.
+
+@samp{#elif} is equivalent to @samp{#else} followed by @samp{#if}, so
+the function will stop at a @samp{#elif} when going backward, but not
+when going forward.
@item C-c C-p
@kindex C-c C-p @r{(C mode)}
argument, move backward.
@item M-a
-@kindex ESC a
+@kindex M-a (C mode)
@findex c-beginning-of-statement
Move point to the beginning of the innermost C statement
(@code{c-beginning-of-statement}). If point is already at the beginning
of a statement, move to the beginning of the preceding statement. With
prefix argument @var{n}, move back @var{n} @minus{} 1 statements.
-If point is within a string or comment, or next to a comment (only
-whitespace between them), this command moves by sentences instead of
-statements.
-
-When called from a program, this function takes three optional
-arguments: the numeric prefix argument, a buffer position limit
-(don't move back before that place), and a flag that controls whether
-to do sentence motion when inside of a comment.
+In comments or in strings which span more than one line, this command
+moves by sentences instead of statements.
@item M-e
-@kindex ESC e
+@kindex M-e (C mode)
@findex c-end-of-statement
-Move point to the end of the innermost C statement; like @kbd{M-a}
-except that it moves in the other direction (@code{c-end-of-statement}).
-
-@item M-x c-backward-into-nomenclature
-@findex c-backward-into-nomenclature
-Move point backward to beginning of a C++ nomenclature section or word.
-With prefix argument @var{n}, move @var{n} times. If @var{n} is
-negative, move forward. C++ nomenclature means a symbol name in the
-style of NamingSymbolsWithMixedCaseAndNoUnderlines; each capital letter
-begins a section or word.
-
-In the GNU project, we recommend using underscores to separate words
-within an identifier in C or C++, rather than using case distinctions.
-
-@item M-x c-forward-into-nomenclature
-@findex c-forward-into-nomenclature
-Move point forward to end of a C++ nomenclature section or word.
-With prefix argument @var{n}, move @var{n} times.
+Move point to the end of the innermost C statement or sentence; like
+@kbd{M-a} except that it moves in the other direction
+(@code{c-end-of-statement}).
@end table
@node Electric C
@subsection Electric C Characters
In C mode and related modes, certain printing characters are
-``electric''---in addition to inserting themselves, they also reindent
-the current line and may insert newlines. This feature is controlled by
-the variable @code{c-auto-newline}. The ``electric'' characters are
-@kbd{@{}, @kbd{@}}, @kbd{:}, @kbd{#}, @kbd{;}, @kbd{,}, @kbd{<},
-@kbd{>}, @kbd{/}, @kbd{*}, @kbd{(}, and @kbd{)}.
-
- Electric characters insert newlines only when the @dfn{auto-newline}
-feature is enabled (indicated by @samp{/a} in the mode line after the
-mode name). This feature is controlled by the variable
-@code{c-auto-newline}. You can turn this feature on or off with the
-command @kbd{C-c C-a}:
+@dfn{electric}---in addition to inserting themselves, they also
+reindent the current line, and optionally also insert newlines. The
+``electric'' characters are @kbd{@{}, @kbd{@}}, @kbd{:}, @kbd{#},
+@kbd{;}, @kbd{,}, @kbd{<}, @kbd{>}, @kbd{/}, @kbd{*}, @kbd{(}, and
+@kbd{)}.
+
+ You might find electric indentation inconvenient if you are editing
+chaotically indented code. If you are new to CC Mode, you might find
+it disconcerting. You can toggle electric action with the command
+@kbd{C-c C-l}; when it is enabled, @samp{/l} appears in the mode line
+after the mode name:
@table @kbd
-@item C-c C-a
-@kindex C-c C-a @r{(C mode)}
-@findex c-toggle-auto-state
-Toggle the auto-newline feature (@code{c-toggle-auto-state}). With a
-prefix argument, this command turns the auto-newline feature on if the
-argument is positive, and off if it is negative.
+@item C-c C-l
+@kindex C-c C-l @r{(C mode)}
+@findex c-toggle-electric-state
+Toggle electric action (@code{c-toggle-electric-state}). With a
+prefix argument, this command enables electric action if the argument
+is positive, disables it if it is negative.
@end table
- The colon character is electric because that is appropriate for a
-single colon. But when you want to insert a double colon in C++, the
-electric behavior of colon is inconvenient. You can insert a double
-colon with no reindentation or newlines by typing @kbd{C-c :}:
+ Electric characters insert newlines only when, in addition to the
+electric state, the @dfn{auto-newline} feature is enabled (indicated
+by @samp{/la} in the mode line after the mode name). You can turn
+this feature on or off with the command @kbd{C-c C-a}:
@table @kbd
-@item C-c :
-@kindex C-c : @r{(C mode)}
-@findex c-scope-operator
-Insert a double colon scope operator at point, without reindenting the
-line or adding any newlines (@code{c-scope-operator}).
+@item C-c C-a
+@kindex C-c C-a @r{(C mode)}
+@findex c-toggle-auto-newline
+Toggle the auto-newline feature (@code{c-toggle-auto-newline}). With a
+prefix argument, this command turns the auto-newline feature on if the
+argument is positive, and off if it is negative.
@end table
- The electric @kbd{#} key reindents the line if it appears to be the
-beginning of a preprocessor directive. This happens when the value of
-@code{c-electric-pound-behavior} is @code{(alignleft)}. You can turn
-this feature off by setting @code{c-electric-pound-behavior} to
-@code{nil}.
-
- The variable @code{c-hanging-braces-alist} controls the insertion of
-newlines before and after inserted braces. It is an association list
-with elements of the following form: @code{(@var{syntactic-symbol}
-. @var{nl-list})}. Most of the syntactic symbols that appear in
-@code{c-offsets-alist} are meaningful here as well.
-
- The list @var{nl-list} may contain either of the symbols
-@code{before} or @code{after}, or both; or it may be @code{nil}. When a
-brace is inserted, the syntactic context it defines is looked up in
-@code{c-hanging-braces-alist}; if it is found, the @var{nl-list} is used
-to determine where newlines are inserted: either before the brace,
-after, or both. If not found, the default is to insert a newline both
-before and after braces.
-
- The variable @code{c-hanging-colons-alist} controls the insertion of
-newlines before and after inserted colons. It is an association list
-with elements of the following form: @code{(@var{syntactic-symbol}
-. @var{nl-list})}. The list @var{nl-list} may contain either of the
-symbols @code{before} or @code{after}, or both; or it may be @code{nil}.
-
- When a colon is inserted, the syntactic symbol it defines is looked
-up in this list, and if found, the @var{nl-list} is used to determine
-where newlines are inserted: either before the brace, after, or both.
-If the syntactic symbol is not found in this list, no newlines are
-inserted.
-
- Electric characters can also delete newlines automatically when the
-auto-newline feature is enabled. This feature makes auto-newline more
-acceptable, by deleting the newlines in the most common cases where you
-do not want them. Emacs can recognize several cases in which deleting a
-newline might be desirable; by setting the variable
-@code{c-cleanup-list}, you can specify @emph{which} of these cases that
-should happen. The variable's value is a list of symbols, each
-describing one case for possible deletion of a newline. Here are the
-meaningful symbols, and their meanings:
-
-@table @code
-@item brace-catch-brace
-Clean up @samp{@} catch (@var{condition}) @{} constructs by placing the
-entire construct on a single line. The clean-up occurs when you type
-the @samp{@{}, if there is nothing between the braces aside from
-@code{catch} and @var{condition}.
-
-@item brace-else-brace
-Clean up @samp{@} else @{} constructs by placing the entire construct on
-a single line. The clean-up occurs when you type the @samp{@{} after
-the @code{else}, but only if there is nothing but white space between
-the braces and the @code{else}.
-
-@item brace-elseif-brace
-Clean up @samp{@} else if (@dots{}) @{} constructs by placing the entire
-construct on a single line. The clean-up occurs when you type the
-@samp{@{}, if there is nothing but white space between the @samp{@}} and
-@samp{@{} aside from the keywords and the @code{if}-condition.
-
-@item empty-defun-braces
-Clean up empty defun braces by placing the braces on the same
-line. Clean-up occurs when you type the closing brace.
-
-@item defun-close-semi
-Clean up the semicolon after a @code{struct} or similar type
-declaration, by placing the semicolon on the same line as the closing
-brace. Clean-up occurs when you type the semicolon.
-
-@item list-close-comma
-Clean up commas following braces in array and aggregate
-initializers. Clean-up occurs when you type the comma.
-
-@item scope-operator
-Clean up double colons which may designate a C++ scope operator, by
-placing the colons together. Clean-up occurs when you type the second
-colon, but only when the two colons are separated by nothing but
-whitespace.
-@end table
+ Usually the CC Mode style configures the exact circumstances in
+which Emacs inserts auto-newlines. You can also configure this
+directly. @xref{Custom Auto-newlines,,, ccmode, The CC Mode Manual}.
@node Hungry Delete
@subsection Hungry Delete Feature in C
+@cindex hungry deletion (C Mode)
- When the @dfn{hungry-delete} feature is enabled (indicated by
-@samp{/h} or @samp{/ah} in the mode line after the mode name), a single
-@key{DEL} command deletes all preceding whitespace, not just one space.
-To turn this feature on or off, use @kbd{C-c C-d}:
+ If you want to delete an entire block of whitespace at point, you
+can use @dfn{hungry deletion}. This deletes all the contiguous
+whitespace either before point or after point in a single operation.
+@dfn{Whitespace} here includes tabs and newlines, but not comments or
+preprocessor commands.
@table @kbd
+@item C-c C-@key{DEL}
+@itemx C-c @key{DEL}
+@findex c-hungry-backspace
+@kindex C-c C-@key{DEL} (C Mode)
+@kindex C-c @key{DEL} (C Mode)
+@code{c-hungry-backspace}---Delete the entire block of whitespace
+preceding point.
+
@item C-c C-d
-@kindex C-c C-d @r{(C mode)}
-@findex c-toggle-hungry-state
-Toggle the hungry-delete feature (@code{c-toggle-hungry-state}). With a
-prefix argument, this command turns the hungry-delete feature on if the
-argument is positive, and off if it is negative.
+@itemx C-c C-@key{DELETE}
+@itemx C-c @key{DELETE}
+@findex c-hungry-delete-forward
+@kindex C-c C-d (C Mode)
+@kindex C-c C-@key{DELETE} (C Mode)
+@kindex C-c @key{DELETE} (C Mode)
+@code{c-hungry-delete-forward}---Delete the entire block of whitespace
+following point.
+@end table
-@item C-c C-t
-@kindex C-c C-t @r{(C mode)}
-@findex c-toggle-auto-hungry-state
-Toggle the auto-newline and hungry-delete features, both at once
-(@code{c-toggle-auto-hungry-state}).
+ As an alternative to the above commands, you can enable @dfn{hungry
+delete mode}. When this feature is enabled (indicated by @samp{/h} in
+the mode line after the mode name), a single @key{DEL} deletes all
+preceding whitespace, not just one space, and a single @kbd{C-c C-d}
+(but @emph{not} plain @key{DELETE}) deletes all following whitespace.
+
+@table @kbd
+@item M-x c-toggle-hungry-state
+@findex c-toggle-hungry-state
+Toggle the hungry-delete feature
+(@code{c-toggle-hungry-state})@footnote{This command had the binding
+@kbd{C-c C-d} in earlier versions of Emacs. @kbd{C-c C-d} is now
+bound to @code{c-hungry-delete-forward}.}. With a prefix argument,
+this command turns the hungry-delete feature on if the argument is
+positive, and off if it is negative.
@end table
@vindex c-hungry-delete-key
@subsection Other Commands for C Mode
@table @kbd
+@item C-c C-w
+@itemx M-x c-subword-mode
+@findex c-subword-mode
+Enable (or disable) @dfn{subword mode}. In subword mode, Emacs's word
+commands then recognize upper case letters in
+@samp{StudlyCapsIdentifiers} as word boundaries. This is indicated by
+the flag @samp{/w} on the mode line after the mode name
+(e.g. @samp{C/law}). You can even use @kbd{M-x c-subword-mode} in
+non-CC Mode buffers.
+
+In the GNU project, we recommend using underscores to separate words
+within an identifier in C or C++, rather than using case distinctions.
+
+@item M-x c-context-line-break
+@findex c-context-line-break
+This command inserts a line break and indents the new line in a manner
+appropriate to the context. In normal code, it does the work of
+@kbd{C-j} (@code{newline-and-indent}), in a C preprocessor line it
+additionally inserts a @samp{\} at the line break, and within comments
+it's like @kbd{M-j} (@code{c-indent-new-comment-line}).
+
+@code{c-context-line-break} isn't bound to a key by default, but it
+needs a binding to be useful. The following code will bind it to
+@kbd{C-j}. We use @code{c-initialization-hook} here to make sure
+the keymap is loaded before we try to change it.
+
+@example
+(defun my-bind-clb ()
+ (define-key c-mode-base-map "\C-j" 'c-context-line-break))
+(add-hook 'c-initialization-hook 'my-bind-clb)
+@end example
+
@item C-M-h
Put mark at the end of a function definition, and put point at the
beginning (@code{c-mark-function}).
@findex c-show-syntactic-information
@kindex C-c C-s @r{(C mode)}
Display the syntactic information about the current source line
-(@code{c-show-syntactic-information}). This is the information that
-directs how the line is indented.
+(@code{c-show-syntactic-information}). This information directs how
+the line is indented.
@item M-x cwarn-mode
@itemx M-x global-cwarn-mode
@findex cwarn-mode
@findex global-cwarn-mode
+@vindex global-cwarn-mode
@cindex CWarn mode
@cindex suspicious constructions in C, C++
CWarn minor mode highlights certain suspicious C and C++ constructions:
names.
@end table
-@node Comments in C
-@subsection Comments in C Modes
-
- C mode and related modes use a number of variables for controlling
-comment format.
-
-@table @code
-@item c-comment-only-line-offset
-@vindex c-comment-only-line-offset
-Extra offset for line which contains only the start of a comment. It
-can be either an integer or a cons cell of the form
-@code{(@var{non-anchored-offset} . @var{anchored-offset})}, where
-@var{non-anchored-offset} is the amount of offset given to
-non-column-zero anchored comment-only lines, and @var{anchored-offset}
-is the amount of offset to give column-zero anchored comment-only lines.
-Just an integer as value is equivalent to @code{(@var{val} . 0)}.
-
-@item c-comment-start-regexp
-@vindex c-comment-start-regexp
-This buffer-local variable specifies how to recognize the start of a comment.
-
-@item c-hanging-comment-ender-p
-@vindex c-hanging-comment-ender-p
-If this variable is @code{nil}, @code{c-fill-paragraph} leaves the
-comment terminator of a block comment on a line by itself. The default
-value is @code{t}, which puts the comment-end delimiter @samp{*/} at the
-end of the last line of the comment text.
-
-@item c-hanging-comment-starter-p
-@vindex c-hanging-comment-starter-p
-If this variable is @code{nil}, @code{c-fill-paragraph} leaves the
-starting delimiter of a block comment on a line by itself. The default
-value is @code{t}, which puts the comment-start delimiter @samp{/*} at
-the beginning of the first line of the comment text.
-@end table
-
-@node Fortran
-@section Fortran Mode
-@cindex Fortran mode
-@cindex mode, Fortran
-
- Fortran mode provides special motion commands for Fortran statements and
-subprograms, and indentation commands that understand Fortran conventions
-of nesting, line numbers and continuation statements. Fortran mode has
-its own Auto Fill mode that breaks long lines into proper Fortran
-continuation lines.
-
- Special commands for comments are provided because Fortran comments
-are unlike those of other languages. Built-in abbrevs optionally save
-typing when you insert Fortran keywords.
-
- Use @kbd{M-x fortran-mode} to switch to this major mode. This command
-runs the hook @code{fortran-mode-hook} (@pxref{Hooks}).
-
-@cindex Fortran77 and Fortran90
-@findex f90-mode
-@findex fortran-mode
- Fortan mode is meant for editing Fortran77 ``fixed format'' source
-code. For editing the modern Fortran90 ``free format'' source code,
-use F90 mode (@code{f90-mode}). Emacs normally uses Fortran mode for
-files with extension @samp{.f}, @samp{.F} or @samp{.for}, and F90 mode
-for the extension @samp{.f90}. GNU Fortran supports both kinds of
-format.
-
-@menu
-* Motion: Fortran Motion. Moving point by statements or subprograms.
-* Indent: Fortran Indent. Indentation commands for Fortran.
-* Comments: Fortran Comments. Inserting and aligning comments.
-* Autofill: Fortran Autofill. Auto fill minor mode for Fortran.
-* Columns: Fortran Columns. Measuring columns for valid Fortran.
-* Abbrev: Fortran Abbrev. Built-in abbrevs for Fortran keywords.
-@end menu
-
-@node Fortran Motion
-@subsection Motion Commands
-
- In addition to the normal commands for moving by and operating on
-``defuns'' (Fortran subprograms---functions and subroutines), Fortran
-mode provides special commands to move by statements.
-
-@table @kbd
-@kindex C-c C-n @r{(Fortran mode)}
-@findex fortran-next-statement
-@item C-c C-n
-Move to beginning of current or next statement
-(@code{fortran-next-statement}).
-
-@kindex C-c C-p @r{(Fortran mode)}
-@findex fortran-previous-statement
-@item C-c C-p
-Move to beginning of current or previous statement
-(@code{fortran-previous-statement}).
-@end table
-
-@node Fortran Indent
-@subsection Fortran Indentation
-
- Special commands and features are needed for indenting Fortran code in
-order to make sure various syntactic entities (line numbers, comment line
-indicators and continuation line flags) appear in the columns that are
-required for standard Fortran.
-
-@menu
-* Commands: ForIndent Commands. Commands for indenting and filling Fortran.
-* Contline: ForIndent Cont. How continuation lines indent.
-* Numbers: ForIndent Num. How line numbers auto-indent.
-* Conv: ForIndent Conv. Conventions you must obey to avoid trouble.
-* Vars: ForIndent Vars. Variables controlling Fortran indent style.
-@end menu
-
-@node ForIndent Commands
-@subsubsection Fortran Indentation and Filling Commands
-
-@table @kbd
-@item C-M-j
-Break the current line and set up a continuation line
-(@code{fortran-split-line}).
-@item M-^
-Join this line to the previous line (@code{fortran-join-line}).
-@item C-M-q
-Indent all the lines of the subprogram point is in
-(@code{fortran-indent-subprogram}).
-@item M-q
-Fill a comment block or statement.
-@end table
-
-@kindex C-M-q @r{(Fortran mode)}
-@findex fortran-indent-subprogram
- The key @kbd{C-M-q} runs @code{fortran-indent-subprogram}, a command
-to reindent all the lines of the Fortran subprogram (function or
-subroutine) containing point.
-
-@kindex C-M-j @r{(Fortran mode)}
-@findex fortran-split-line
- The key @kbd{C-M-j} runs @code{fortran-split-line}, which splits
-a line in the appropriate fashion for Fortran. In a non-comment line,
-the second half becomes a continuation line and is indented
-accordingly. In a comment line, both halves become separate comment
-lines.
-
-@kindex M-^ @r{(Fortran mode)}
-@kindex C-c C-d @r{(Fortran mode)}
-@findex fortran-join-line
- @kbd{M-^} or @kbd{C-c C-d} runs the command @code{fortran-join-line},
-which joins a continuation line back to the previous line, roughly as
-the inverse of @code{fortran-split-line}. The point must be on a
-continuation line when this command is invoked.
-
-@kindex M-q @r{(Fortran mode)}
-@kbd{M-q} in Fortran mode fills the comment block or statement that
-point is in. This removes any excess statement continuations.
-
-@node ForIndent Cont
-@subsubsection Continuation Lines
-@cindex Fortran continuation lines
-
-@vindex fortran-continuation-string
- Most modern Fortran compilers allow two ways of writing continuation
-lines. If the first non-space character on a line is in column 5, then
-that line is a continuation of the previous line. We call this
-@dfn{fixed format}. (In GNU Emacs we always count columns from 0.) The
-variable @code{fortran-continuation-string} specifies what character to
-put on column 5. A line that starts with a tab character followed by
-any digit except @samp{0} is also a continuation line. We call this
-style of continuation @dfn{tab format}.
-
-@vindex indent-tabs-mode @r{(Fortran mode)}
- Fortran mode can make either style of continuation line, but you
-must specify which one you prefer. The value of the variable
-@code{indent-tabs-mode} controls the choice: @code{nil} for fixed
-format, and non-@code{nil} for tab format. You can tell which style
-is presently in effect by the presence or absence of the string
-@samp{Tab} in the mode line.
-
- If the text on a line starts with the conventional Fortran
-continuation marker @samp{$}, or if it begins with any non-whitespace
-character in column 5, Fortran mode treats it as a continuation line.
-When you indent a continuation line with @key{TAB}, it converts the line
-to the current continuation style. When you split a Fortran statement
-with @kbd{C-M-j}, the continuation marker on the newline is created
-according to the continuation style.
-
- The setting of continuation style affects several other aspects of
-editing in Fortran mode. In fixed format mode, the minimum column
-number for the body of a statement is 6. Lines inside of Fortran
-blocks that are indented to larger column numbers always use only the
-space character for whitespace. In tab format mode, the minimum
-column number for the statement body is 8, and the whitespace before
-column 8 must always consist of one tab character.
-
-@vindex fortran-tab-mode-default
-@vindex fortran-analyze-depth
- When you enter Fortran mode for an existing file, it tries to deduce the
-proper continuation style automatically from the file contents. The first
-line that begins with either a tab character or six spaces determines the
-choice. The variable @code{fortran-analyze-depth} specifies how many lines
-to consider (at the beginning of the file); if none of those lines
-indicates a style, then the variable @code{fortran-tab-mode-default}
-specifies the style. If it is @code{nil}, that specifies fixed format, and
-non-@code{nil} specifies tab format.
-
-@node ForIndent Num
-@subsubsection Line Numbers
-
- If a number is the first non-whitespace in the line, Fortran
-indentation assumes it is a line number and moves it to columns 0
-through 4. (Columns always count from 0 in GNU Emacs.)
-
-@vindex fortran-line-number-indent
- Line numbers of four digits or less are normally indented one space.
-The variable @code{fortran-line-number-indent} controls this; it
-specifies the maximum indentation a line number can have. Line numbers
-are indented to right-justify them to end in column 4 unless that would
-require more than this maximum indentation. The default value of the
-variable is 1.
-
-@vindex fortran-electric-line-number
- Simply inserting a line number is enough to indent it according to
-these rules. As each digit is inserted, the indentation is recomputed.
-To turn off this feature, set the variable
-@code{fortran-electric-line-number} to @code{nil}. Then inserting line
-numbers is like inserting anything else.
-
-@node ForIndent Conv
-@subsubsection Syntactic Conventions
-
- Fortran mode assumes that you follow certain conventions that simplify
-the task of understanding a Fortran program well enough to indent it
-properly:
-
-@itemize @bullet
-@item
-Two nested @samp{do} loops never share a @samp{continue} statement.
-
-@item
-Fortran keywords such as @samp{if}, @samp{else}, @samp{then}, @samp{do}
-and others are written without embedded whitespace or line breaks.
-
-Fortran compilers generally ignore whitespace outside of string
-constants, but Fortran mode does not recognize these keywords if they
-are not contiguous. Constructs such as @samp{else if} or @samp{end do}
-are acceptable, but the second word should be on the same line as the
-first and not on a continuation line.
-@end itemize
-
-@noindent
-If you fail to follow these conventions, the indentation commands may
-indent some lines unaesthetically. However, a correct Fortran program
-retains its meaning when reindented even if the conventions are not
-followed.
-
-@node ForIndent Vars
-@subsubsection Variables for Fortran Indentation
-
-@vindex fortran-do-indent
-@vindex fortran-if-indent
-@vindex fortran-structure-indent
-@vindex fortran-continuation-indent
-@vindex fortran-check-all-num@dots{}
-@vindex fortran-minimum-statement-indent@dots{}
- Several additional variables control how Fortran indentation works:
-
-@table @code
-@item fortran-do-indent
-Extra indentation within each level of @samp{do} statement (default 3).
-
-@item fortran-if-indent
-Extra indentation within each level of @samp{if} statement (default 3).
-This value is also used for extra indentation within each level of the
-Fortran 90 @samp{where} statement.
-
-@item fortran-structure-indent
-Extra indentation within each level of @samp{structure}, @samp{union}, or
-@samp{map} statements (default 3).
-
-@item fortran-continuation-indent
-Extra indentation for bodies of continuation lines (default 5).
-
-@item fortran-check-all-num-for-matching-do
-If this is @code{nil}, indentation assumes that each @samp{do} statement
-ends on a @samp{continue} statement. Therefore, when computing
-indentation for a statement other than @samp{continue}, it can save time
-by not checking for a @samp{do} statement ending there. If this is
-non-@code{nil}, indenting any numbered statement must check for a
-@samp{do} that ends there. The default is @code{nil}.
-
-@item fortran-blink-matching-if
-If this is @code{t}, indenting an @samp{endif} statement moves the
-cursor momentarily to the matching @samp{if} statement to show where it
-is. The default is @code{nil}.
-
-@item fortran-minimum-statement-indent-fixed
-Minimum indentation for fortran statements when using fixed format
-continuation line style. Statement bodies are never indented less than
-this much. The default is 6.
-
-@item fortran-minimum-statement-indent-tab
-Minimum indentation for fortran statements for tab format continuation line
-style. Statement bodies are never indented less than this much. The
-default is 8.
-@end table
-
-@node Fortran Comments
-@subsection Fortran Comments
-
- The usual Emacs comment commands assume that a comment can follow a line
-of code. In Fortran, the standard comment syntax requires an entire line
-to be just a comment. Therefore, Fortran mode replaces the standard Emacs
-comment commands and defines some new variables.
-
- Fortran mode can also handle the Fortran90 comment syntax where comments
-start with @samp{!} and can follow other text. Because only some Fortran77
-compilers accept this syntax, Fortran mode will not insert such comments
-unless you have said in advance to do so. To do this, set the variable
-@code{comment-start} to @samp{"!"} (@pxref{Variables}).
-
-@table @kbd
-@item M-;
-Align comment or insert new comment (@code{fortran-comment-indent}).
-
-@item C-x ;
-Applies to nonstandard @samp{!} comments only.
-
-@item C-c ;
-Turn all lines of the region into comments, or (with argument) turn them back
-into real code (@code{fortran-comment-region}).
-@end table
-
- @kbd{M-;} in Fortran mode is redefined as the command
-@code{fortran-comment-indent}. Like the usual @kbd{M-;} command, this
-recognizes any kind of existing comment and aligns its text appropriately;
-if there is no existing comment, a comment is inserted and aligned. But
-inserting and aligning comments are not the same in Fortran mode as in
-other modes.
-
- When a new comment must be inserted, if the current line is blank, a
-full-line comment is inserted. On a non-blank line, a nonstandard @samp{!}
-comment is inserted if you have said you want to use them. Otherwise a
-full-line comment is inserted on a new line before the current line.
-
- Nonstandard @samp{!} comments are aligned like comments in other
-languages, but full-line comments are different. In a standard full-line
-comment, the comment delimiter itself must always appear in column zero.
-What can be aligned is the text within the comment. You can choose from
-three styles of alignment by setting the variable
-@code{fortran-comment-indent-style} to one of these values:
-
-@vindex fortran-comment-indent-style
-@vindex fortran-comment-line-extra-indent
-@table @code
-@item fixed
-Align the text at a fixed column, which is the sum of
-@code{fortran-comment-line-extra-indent} and the minimum statement
-indentation. This is the default.
-
-The minimum statement indentation is
-@code{fortran-minimum-statement-indent-fixed} for fixed format
-continuation line style and @code{fortran-minimum-statement-indent-tab}
-for tab format style.
-
-@item relative
-Align the text as if it were a line of code, but with an additional
-@code{fortran-comment-line-extra-indent} columns of indentation.
-
-@item nil
-Don't move text in full-line comments automatically at all.
-@end table
-
-@vindex fortran-comment-indent-char
- In addition, you can specify the character to be used to indent within
-full-line comments by setting the variable
-@code{fortran-comment-indent-char} to the single-character string you want
-to use.
-
-@vindex comment-line-start
-@vindex comment-line-start-skip
- Fortran mode introduces two variables @code{comment-line-start} and
-@code{comment-line-start-skip}, which play for full-line comments the same
-roles played by @code{comment-start} and @code{comment-start-skip} for
-ordinary text-following comments. Normally these are set properly by
-Fortran mode, so you do not need to change them.
-
- The normal Emacs comment command @kbd{C-x ;} has not been redefined. If
-you use @samp{!} comments, this command can be used with them. Otherwise
-it is useless in Fortran mode.
-
-@kindex C-c ; @r{(Fortran mode)}
-@findex fortran-comment-region
-@vindex fortran-comment-region
- The command @kbd{C-c ;} (@code{fortran-comment-region}) turns all the
-lines of the region into comments by inserting the string @samp{C$$$} at
-the front of each one. With a numeric argument, it turns the region
-back into live code by deleting @samp{C$$$} from the front of each line
-in it. The string used for these comments can be controlled by setting
-the variable @code{fortran-comment-region}. Note that here we have an
-example of a command and a variable with the same name; these two uses
-of the name never conflict because in Lisp and in Emacs it is always
-clear from the context which one is meant.
-
-@node Fortran Autofill
-@subsection Fortran Auto Fill Mode
-
- Fortran Auto Fill mode is a minor mode which automatically splits
-Fortran statements as you insert them when they become too wide.
-Splitting a statement involves making continuation lines using
-@code{fortran-continuation-string} (@pxref{ForIndent Cont}). This
-splitting happens when you type @key{SPC}, @key{RET}, or @key{TAB}, and
-also in the Fortran indentation commands.
-
-@findex fortran-auto-fill-mode
- @kbd{M-x fortran-auto-fill-mode} turns Fortran Auto Fill mode on if it
-was off, or off if it was on. This command works the same as @kbd{M-x
-auto-fill-mode} does for normal Auto Fill mode (@pxref{Filling}). A
-positive numeric argument turns Fortran Auto Fill mode on, and a
-negative argument turns it off. You can see when Fortran Auto Fill mode
-is in effect by the presence of the word @samp{Fill} in the mode line,
-inside the parentheses. Fortran Auto Fill mode is a minor mode, turned
-on or off for each buffer individually. @xref{Minor Modes}.
-
-@vindex fortran-break-before-delimiters
- Fortran Auto Fill mode breaks lines at spaces or delimiters when the
-lines get longer than the desired width (the value of @code{fill-column}).
-The delimiters that Fortran Auto Fill mode may break at are @samp{,},
-@samp{'}, @samp{+}, @samp{-}, @samp{/}, @samp{*}, @samp{=}, and @samp{)}.
-The line break comes after the delimiter if the variable
-@code{fortran-break-before-delimiters} is @code{nil}. Otherwise (and by
-default), the break comes before the delimiter.
-
- By default, Fortran Auto Fill mode is not enabled. If you want this
-feature turned on permanently, add a hook function to
-@code{fortran-mode-hook} to execute @code{(fortran-auto-fill-mode 1)}.
-@xref{Hooks}.
-
-@node Fortran Columns
-@subsection Checking Columns in Fortran
-
-@table @kbd
-@item C-c C-r
-Display a ``column ruler'' momentarily above the current line
-(@code{fortran-column-ruler}).
-@item C-c C-w
-Split the current window horizontally temporarily so that it is 72
-columns wide (@code{fortran-window-create-momentarily}). This may
-help you avoid making lines longer than the 72-character limit that
-some Fortran compilers impose.
-@item C-u C-c C-w
-Split the current window horizontally so that it is 72 columns wide
-(@code{fortran-window-create}). You can then continue editing.
-@item M-x fortran-strip-sequence-nos
-Delete all text in column 72 and beyond.
-@end table
-
-@kindex C-c C-r @r{(Fortran mode)}
-@findex fortran-column-ruler
- The command @kbd{C-c C-r} (@code{fortran-column-ruler}) shows a column
-ruler momentarily above the current line. The comment ruler is two lines
-of text that show you the locations of columns with special significance in
-Fortran programs. Square brackets show the limits of the columns for line
-numbers, and curly brackets show the limits of the columns for the
-statement body. Column numbers appear above them.
-
- Note that the column numbers count from zero, as always in GNU Emacs.
-As a result, the numbers may be one less than those you are familiar
-with; but the positions they indicate in the line are standard for
-Fortran.
-
-@vindex fortran-column-ruler-fixed
-@vindex fortran-column-ruler-tabs
- The text used to display the column ruler depends on the value of
-the variable @code{indent-tabs-mode}. If @code{indent-tabs-mode} is
-@code{nil}, then the value of the variable
-@code{fortran-column-ruler-fixed} is used as the column ruler.
-Otherwise, the variable @code{fortran-column-ruler-tab} is displayed.
-By changing these variables, you can change the column ruler display.
-
-@kindex C-c C-w @r{(Fortran mode)}
-@findex fortran-window-create-momentarily
- @kbd{C-c C-w} (@code{fortran-window-create-momentarily}) temporarily
-splits the current window horizontally, making a window 72 columns
-wide, so you can see which lines that is too long. Type a space to
-restore the normal width.
-
-@kindex C-u C-c C-w @r{(Fortran mode)}
-@findex fortran-window-create
- You can also split the window horizontally and continue editing with
-the split in place. To do this, use @kbd{C-u C-c C-w} (@code{M-x
-fortran-window-create}). By editing in this window you can
-immediately see when you make a line too wide to be correct Fortran.
-
-@findex fortran-strip-sequence-nos
- The command @kbd{M-x fortran-strip-sequence-nos} deletes all text in
-column 72 and beyond, on all lines in the current buffer. This is the
-easiest way to get rid of old sequence numbers.
-
-@node Fortran Abbrev
-@subsection Fortran Keyword Abbrevs
-
- Fortran mode provides many built-in abbrevs for common keywords and
-declarations. These are the same sort of abbrev that you can define
-yourself. To use them, you must turn on Abbrev mode. @xref{Abbrevs}.
-
- The built-in abbrevs are unusual in one way: they all start with a
-semicolon. You cannot normally use semicolon in an abbrev, but Fortran
-mode makes this possible by changing the syntax of semicolon to ``word
-constituent.''
-
- For example, one built-in Fortran abbrev is @samp{;c} for
-@samp{continue}. If you insert @samp{;c} and then insert a punctuation
-character such as a space or a newline, the @samp{;c} expands automatically
-to @samp{continue}, provided Abbrev mode is enabled.@refill
-
- Type @samp{;?} or @samp{;C-h} to display a list of all the built-in
-Fortran abbrevs and what they stand for.
-
@node Asm Mode
@section Asm Mode
The variable @code{asm-comment-char} specifies which character
starts comments in assembler syntax.
+
+@ifnottex
+@include fortran-xtra.texi
+@end ifnottex
+
+@ignore
+ arch-tag: c7ee7409-40a4-45c7-bfb7-ae7f2c74d0c0
+@end ignore