1 #+SETUPFILE: org-setup.inc
7 *** Quickly finding snippets
9 There are some ways you can quickly find a snippet file:
11 - =M-x yas-new-snippet=
13 Prompts you for a snippet name, then tries to guess a suitable
14 directory to store it, prompting you for creation if it does not
15 exist. Finally, places you in a new buffer set to =snippet-mode= so
16 you can write your snippet.
18 - =M-x yas-find-snippets=
20 Lets you find the snippet file in the directory the snippet was
21 loaded from (if it exists) like =find-file-other-window=. The
22 directory searching logic is similar to =M-x yas-new-snippet=.
24 - =M-x yas-visit-snippet-file=
26 Prompts you for possible snippet expansions like
27 [[sym:yas-insert-snippet][=yas-insert-snippet=]], but instead of expanding it, takes you directly
28 to the snippet definition's file, if it exists.
30 Once you find this file it will be set to =snippet-mode= (see ahead) and
31 you can start editing your snippet.
33 *** Using the =snippet-mode= major mode
35 There is a major mode =snippet-mode= to edit snippets. You can set the
36 buffer to this mode with =M-x snippet-mode=. It provides reasonably
37 useful syntax highlighting.
39 Two commands are defined in this mode:
41 - =M-x yas-load-snippet-buffer=
44 When editing a snippet, this loads the snippet into the correct
45 mode and menu. Bound to =C-c C-c= by default while in
49 - =M-x yas-tryout-snippet=
52 When editing a snippet, this opens a new empty buffer, sets it to
53 the appropriate major mode and inserts the snippet there, so you
54 can see what it looks like. This is bound to =C-c C-t= while in
58 There are also /snippets for writing snippets/: =vars=, =$f= and =$m=
63 A file defining a snippet generally contains the template to be
66 Optionally, if the file contains a line of =# --=, the lines above it
67 count as comments, some of which can be /directives/ (or meta data).
68 Snippet directives look like =# property: value= and tweak certain
69 snippets properties described below. If no =# --= is found, the whole
70 file is considered the snippet template.
72 Here's a typical example:
75 # contributor: pluskid <pluskid@gmail.com>
81 Here's a list of currently supported directives:
83 *** =# key:= snippet abbrev
85 This is the probably the most important directive, it's the abbreviation
86 you type to expand a snippet just before hitting [[sym:yas-trigger-key][=yas-trigger-key=]]. If
87 you don't specify this the snippet will not be expandable through the
90 *** =# name:= snippet name
92 This is a one-line description of the snippet. It will be displayed in
93 the menu. It's a good idea to select a descriptive name for a snippet --
94 especially distinguishable among similar snippets.
96 If you omit this name it will default to the file name the snippet was
99 *** =# condition:= snippet condition
101 This is a piece of Emacs-lisp code. If a snippet has a condition, then
102 it will only be expanded when the condition code evaluate to some
105 See also [[sym:yas-buffer-local-condition][=yas-buffer-local-condition=]] in
106 [[./snippet-expansion.org][Expanding snippets]]
108 *** =# group:= snippet menu grouping
110 When expanding/visiting snippets from the menu-bar menu, snippets for a
111 given mode can be grouped into sub-menus . This is useful if one has too
112 many snippets for a mode which will make the menu too long.
114 The =# group:= property only affect menu construction (See
115 [[./snippet-menu.org][the YASnippet menu]]) and the same effect can be
116 achieved by grouping snippets into sub-directories and using the
117 =.yas-make-groups= special file (for this see
118 [[./snippet-organization.org][Organizing Snippets]]
120 Refer to the bundled snippets for =ruby-mode= for examples on the
121 =# group:= directive. Group can also be nested, e.g.
122 =control structure.loops= tells that the snippet is under the =loops=
123 group which is under the =control structure= group.
125 *** =# expand-env:= expand environment
127 This is another piece of Emacs-lisp code in the form of a =let= /varlist
128 form/, i.e. a list of lists assigning values to variables. It can be
129 used to override variable values while the snippet is being expanded.
131 Interesting variables to override are [[sym:yas-wrap-around-region][=yas-wrap-around-region=]] and
132 [[sym:yas-indent-line][=yas-indent-line=]] (see [[./snippet-expansion.org][Expanding Snippets]]).
134 As an example, you might normally have [[sym:yas-indent-line][=yas-indent-line=]] set to '=auto=
135 and [[sym:yas-wrap-around-region][=yas-wrap-around-region=]] set to =t=, but for this particularly
136 brilliant piece of ASCII art these values would mess up your hard work.
141 # expand-env: ((yas-indent-line 'fixed) (yas-wrap-around-region 'nil))
155 *** =# binding:= direct keybinding
157 You can use this directive to expand a snippet directly from a normal
158 Emacs keybinding. The keybinding will be registered in the Emacs keymap
159 named after the major mode the snippet is active for.
161 Additionally a variable [[sym:yas-prefix][=yas-prefix=]] is set to to the prefix argument
162 you normally use for a command. This allows for small variations on the
163 same snippet, for example in this "html-mode" snippet.
167 # binding: C-c C-c C-m
169 <p>`(when yas-prefix "\n")`$0`(when yas-prefix "\n")`</p>
172 This binding will be recorded in the keymap =html-mode-map=. To expand a
173 paragraph tag newlines, just press =C-u C-c C-c C-m=. Omitting the =C-u=
174 will expand the paragraph tag without newlines.
176 *** =# contributor:= snippet author
178 This is optional and has no effect whatsoever on snippet functionality,
183 The syntax of the snippet template is simple but powerful, very similar
188 Arbitrary text can be included as the content of a template. They are
189 usually interpreted as plain text, except =$= and ==. You need to
190 use \` to escape them: =\$= and =\=. The \` itself may also needed to be
191 escaped as =\\= sometimes.
193 *** Embedded Emacs-lisp code
195 Emacs-Lisp code can be embedded inside the template, written inside
196 back-quotes (==). The lisp forms are evaluated when the snippet is
197 being expanded. The evaluation is done in the same buffer as the
198 snippet being expanded.
200 Here's an example for c-mode` to calculate the header file guard
204 #ifndef ${1:_`(upcase (file-name-nondirectory (file-name-sans-extension (buffer-file-name))))`_H_}
212 From version 0.6, snippets expansions are run with some special
213 Emacs-lisp variables bound. One of this is [[sym:yas-selected-text][=yas-selected-text=]]. You can
214 therefore define a snippet like:
218 `yas-selected-text`$0
222 to "wrap" the selected region inside your recently inserted snippet.
223 Alternatively, you can also customize the variable
224 [[sym:yas-wrap-around-region][=yas-wrap-around-region=]] to =t= which will do this automatically.
228 Tab stops are fields that you can navigate back and forth by =TAB= and
229 =S-TAB=. They are written by =$= followed with a number. =$0= has the
230 special meaning of the /exit point/ of a snippet. That is the last place
231 to go when you've traveled all the fields. Here's a typical example:
238 *** Placeholder fields
240 Tab stops can have default values -- a.k.a placeholders. The syntax is
247 They acts as the default value for a tab stop. But when you firstly
248 type at a tab stop, the default value will be replaced by your typing.
249 The number can be omitted if you don't want to create [[mirrors]] or
250 [[transformations]] for this field.
254 We refer the tab stops with placeholders as a /field/. A field can have
255 mirrors. Its mirrors will get updated when you change the text of a
256 field. Here's an example:
259 \begin{${1:enumerate}}
264 When you type "document" at =${1:enumerate}=, the word "document" will
265 also be inserted at =\end{$1}=. The best explanation is to see the
266 screencast([[http://www.youtube.com/watch?v=vOj7btx3ATg][YouTube]] or [[http://yasnippet.googlecode.com/files/yasnippet.avi][avi video]]).
268 The tab stops with the same number to the field act as its mirrors. If
269 none of the tab stops has an initial value, the first one is selected as
270 the field and others mirrors.
272 *** Mirrors with <<transformations>>
274 If the value of an =${n:=-construct starts with and contains =$(=, then
275 it is interpreted as a mirror for field =n= with a transformation. The
276 mirror's text content is calculated according to this transformation,
277 which is Emacs-lisp code that gets evaluated in an environment where the
278 variable =text= (or [[sym:yas-text][=yas-text=]]) is bound to the text content (string)
279 contained in the field =n=.Here's an example for Objective-C:
287 - (void)set${2:$(capitalize text)}:($1)aValue
290 $2 = [aValue retain];
295 Look at =${2:$(capitalize text)}=, it is a mirror with transformation
296 instead of a field. The actual field is at the first line: =${2:foo}=.
297 When you type text in =${2:foo}=, the transformation will be evaluated
298 and the result will be placed there as the transformed text. So in this
299 example, if you type "baz" in the field, the transformed text will be
300 "Baz". This example is also available in the screencast.
302 Another example is for =rst-mode=. In reStructuredText, the document
303 title can be some text surrounded by "===" below and above. The "==="
304 should be at least as long as the text. So
320 is not. Here's an snippet for rst title:
323 ${1:$(make-string (string-width text) ?\=)}
325 ${1:$(make-string (string-width text) ?\=)}
330 *** Fields with transformations
332 From version 0.6 on, you can also have lisp transformation inside
333 fields. These work mostly mirror transformations but are evaluated when
334 you first enter the field, after each change you make to the field and
335 also just before you exit the field.
337 The syntax is also a tiny bit different, so that the parser can
338 distinguish between fields and mirrors. In the following example
340 : #define "${1:mydefine$(upcase yas-text)}"
342 =mydefine= gets automatically upcased to =MYDEFINE= once you enter the
343 field. As you type text, it gets filtered through the transformation
346 Note that to tell this kind of expression from a mirror with a
347 transformation, YASnippet needs extra text between the =:= and the
348 transformation's =$=. If you don't want this extra-text, you can use two
351 : #define "${1:$$(upcase yas-text)}"
353 Please note that as soon as a transformation takes place, it changes the
354 value of the field and sets it its internal modification state to
355 =true=. As a consequence, the auto-deletion behaviour of normal fields
356 does not take place. This is by design.
358 *** Choosing fields value from a list and other tricks
360 As mentioned, the field transformation is invoked just after you enter
361 the field, and with some useful variables bound, notably
362 [[sym:yas-modified-p][=yas-modified-p=]] and [[sym:yas-moving-away-p][=yas-moving-away-p=]]. Because of this feature you
363 can place a transformation in the primary field that lets you select
364 default values for it.
366 The [[sym:yas-choose-value][=yas-choose-value=]] does this work for you. For example:
369 <div align="${2:$$(yas-choose-value '("right" "center" "left"))}">
374 See the definition of [[sym:yas-choose-value][=yas-choose-value=]] to see how it was written using
377 Here's another use, for LaTeX-mode, which calls reftex-label just as you
378 enter snippet field 2. This one makes use of [[sym:yas-modified-p][=yas-modified-p=]] directly.
381 \section{${1:"Titel der Tour"}}%
383 \label{{2:"waiting for reftex-label call..."$(unless yas-modified-p (reftex-label nil 'dont-
387 The function [[sym:yas-verify-value][=yas-verify-value=]] has another neat trick, and makes use of
388 [[sym:yas-moving-away-p][=yas-moving-away-p=]]. Try it and see! Also, check out this
389 [[http://groups.google.com/group/smart-snippet/browse_thread/thread/282a90a118e1b662][thread]]
391 *** Nested placeholder fields
393 From version 0.6 on, you can also have nested placeholders of the type:
396 <div${1: id="${2:some_id}"}>$0</div>
399 This allows you to choose if you want to give this =div= an =id=
400 attribute. If you tab forward after expanding it will let you change
401 "some\_id" to whatever you like. Alternatively, you can just press =C-d=
402 (which executes [[sym:yas-skip-and-clear-or-delete-char][=yas-skip-and-clear-or-delete-char=]]) and go straight to
405 By the way, =C-d= will only clear the field if you cursor is at the
406 beginning of the field /and/ it hasn't been changed yet. Otherwise, it
407 performs the normal Emacs =delete-char= command.
409 ** Importing TextMate snippets
411 There are a couple of tools that take TextMate's ".tmSnippet" xml files
412 and create YASnippet definitions:
416 - [[http://code.nokrev.com/?p=snippet-copier.git;a=blob_plain;f=snippet_copier.py][a python script by Jeff Wheeler]]
418 - a [[http://yasnippet.googlecode.com/svn/trunk/extras/textmate_import.rb][ruby tool]] , =textmate_import.rb= adapted from [[http://www.neutronflux.net/2009/07/28/shoulda-snippets-for-emacs/][Rob Christie's]],
419 which I have uploaded to the repository.
423 In this section, i'll shortly cover the *second* option.
425 Download the =textmate_import.rb= tool and the TextMate bundle you're
429 $ curl -O http://yasnippet.googlecode.com/svn/trunk/extras/textmate_import.rb
430 $ svn export http://svn.textmate.org/trunk/Bundles/HTML.tmbundle/
433 Then invoke =textmate_import.rb= like this:
436 $ ./textmate_import.rb -d HTML.tmbundle/Snippets/ -o html-mode -g HTML.tmbundle/info.plist
439 You should end up with a =html-mode= subdir containing snippets exported
443 $ tree html-mode # to view dir contents, if you have 'tree' installed
446 The =-g= is optional but helps the tool figure out the grouping.
447 According to [[./snippet-organization.org][Organizing Snippets]], don't forget to touch
448 =.yas-make-groups= and =.yas-ignore-filename-triggers= inside the
451 Also try =textmate_import.rb --help= for a list of options.
453 Please note that snippet importation is not yet perfect. You'll probably
454 have some adjustments to some/many snippets. Please contribute these
455 adjustments to the google group or, better yet, patch the
456 =textmate_import.rb= to automatically perform them and submit that.