-;;; pcase.el --- ML-style pattern-matching macro for Elisp -*- lexical-binding: t; coding: utf-8 -*-
+;;; pcase.el --- ML-style pattern-matching macro for Elisp -*- lexical-binding: t -*-
-;; Copyright (C) 2010-2015 Free Software Foundation, Inc.
+;; Copyright (C) 2010-2016 Free Software Foundation, Inc.
;; Author: Stefan Monnier <monnier@iro.umontreal.ca>
;; Keywords:
;;;###autoload
(defmacro pcase (exp &rest cases)
- "Perform ML-style pattern matching on EXP.
+ "Eval EXP and perform ML-style pattern matching on that value.
CASES is a list of elements of the form (PATTERN CODE...).
Patterns can take the following forms:
SYMBOL matches anything and binds it to SYMBOL.
(or PAT...) matches if any of the patterns matches.
(and PAT...) matches if all the patterns match.
- 'VAL matches if the object is `equal' to VAL
- ATOM is a shorthand for 'ATOM.
+ \\='VAL matches if the object is `equal' to VAL.
+ ATOM is a shorthand for \\='ATOM.
ATOM can be a keyword, an integer, or a string.
(pred FUN) matches if FUN applied to the object returns non-nil.
(guard BOOLEXP) matches if BOOLEXP evaluates to non-nil.
which is the value being matched.
So a FUN of the form SYMBOL is equivalent to one of the form (FUN).
FUN can refer to variables bound earlier in the pattern.
-FUN is assumed to be pure, i.e. it can be dropped if its result is not used,
-and two identical calls can be merged into one.
E.g. you can match pairs where the cdr is larger than the car with a pattern
like \\=`(,a . ,(pred (< a))) or, with more checks:
\\=`(,(and a (pred numberp)) . ,(and (pred numberp) (pred (< a))))
+FUN is assumed to be pure, i.e. it can be dropped if its result is not used,
+and two identical calls can be merged into one.
Additional patterns can be defined via `pcase-defmacro'.
Currently, the following patterns are provided this way:"
expansion))))
(declare-function help-fns--signature "help-fns"
- (function doc real-def real-function raw))
+ (function doc real-def real-function buffer))
;; FIXME: Obviously, this will collide with nadvice's use of
;; function-documentation if we happen to advise `pcase'.
(insert "\n\n-- ")
(let* ((doc (documentation me 'raw)))
(setq doc (help-fns--signature symbol doc me
- (indirect-function me) t))
+ (indirect-function me) nil))
(insert "\n" (or doc "Not documented.")))))))
(let ((combined-doc (buffer-string)))
(if ud (help-add-fundoc-usage combined-doc (car ud)) combined-doc)))))
((memq upat '(t _))
(let ((code (pcase--u1 matches code vars rest)))
(if (eq upat '_) code
- (message "%s"
- "Pattern t is deprecated. Use `_' instead")
- code)))
+ (macroexp--warn-and-return
+ "Pattern t is deprecated. Use `_' instead"
+ code))))
((eq upat 'pcase--dontcare) :pcase--dontcare)
((memq (car-safe upat) '(guard pred))
(if (eq (car upat) 'pred) (pcase--mark-used sym))
(def-edebug-spec
pcase-QPAT
+ ;; Cf. edebug spec for `backquote-form' in edebug.el.
(&or ("," pcase-PAT)
- (pcase-QPAT . pcase-QPAT)
+ (pcase-QPAT [&rest [¬ ","] pcase-QPAT]
+ . [&or nil pcase-QPAT])
(vector &rest pcase-QPAT)
sexp))