From: Lars Ingebrigtsen <larsi@gnus.org>
Date: Tue, 8 Feb 2022 07:51:30 +0000 (+0100)
Subject: Document pcase-lambda
X-Git-Tag: emacs-29.0.90~2433
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=a512940daa046cc529c679942431435175cd6903;p=emacs.git

Document pcase-lambda

* doc/lispref/control.texi (Destructuring with pcase Patterns):
Document pcase-lambda (bug#20268).
---

diff --git a/doc/lispref/control.texi b/doc/lispref/control.texi
index 634d46a7854..2f1666ba771 100644
--- a/doc/lispref/control.texi
+++ b/doc/lispref/control.texi
@@ -1326,6 +1326,20 @@ Assign values to variables in a @code{setq} form, destructuring each
 @var{value} according to its respective @var{pattern}.
 @end defmac
 
+@defmac pcase-lambda lambda-list &rest body
+This is like @code{lambda}, but allows each argument to be a pattern.
+For instance, here's a simple function that takes a cons cell as the
+argument:
+
+@example
+(setq fun
+      (pcase-lambda (`(,key . ,val))
+        (vector key (* val 10))))
+(funcall fun '(foo . 2))
+    @result{} [foo 20]
+@end example
+@end defmac
+
 @node Iteration
 @section Iteration
 @cindex iteration