Add an optional testfn parameter to assoc

* src/fns.c (assoc): New optional testfn parameter used for comparison
when provided.
* test/src/fns-tests.el (test-assoc-testfn): Add tests for the new
'testfn' parameter.
* src/buffer.c:
* src/coding.c:
* src/dbusbind.c:
* src/font.c:
* src/fontset.c:
* src/gfilenotify.c:
* src/image.c:
* src/keymap.c:
* src/process.c:
* src/w32fns.c:
* src/w32font.c:
* src/w32notify.c:
* src/w32term.c:
* src/xdisp.c:
* src/xfont.c: Add a third argument to Fassoc calls.
* etc/NEWS:
* doc/lispref/lists.texi: Document the new 'testfn' parameter.

1 files changed, 9 insertions, 9 deletions

diff --git a/doc/lispref/lists.texi b/doc/lispref/lists.texi
index 8eab2818f97..966d8f18b17 100644
--- a/doc/lispref/lists.texi
+++ b/doc/lispref/lists.texi
@@ -1511,12 +1511,12 @@ respects.  A property list behaves like an association list in which
 each key can occur only once.  @xref{Property Lists}, for a comparison
 of property lists and association lists.
 
-@defun assoc key alist
+@defun assoc key alist &optional testfn
 This function returns the first association for @var{key} in
 @var{alist}, comparing @var{key} against the alist elements using
-@code{equal} (@pxref{Equality Predicates}).  It returns @code{nil} if no
-association in @var{alist} has a @sc{car} @code{equal} to @var{key}.
-For example:
+@var{testfn} if non-nil, or @code{equal} if nil (@pxref{Equality
+Predicates}).  It returns @code{nil} if no association in @var{alist}
+has a @sc{car} equal to @var{key}.  For example:
 
 @smallexample
 (setq trees '((pine . cones) (oak . acorns) (maple . seeds)))
@@ -1561,11 +1561,11 @@ this as reverse @code{assoc}, finding the key for a given value.
 @defun assq key alist
 This function is like @code{assoc} in that it returns the first
 association for @var{key} in @var{alist}, but it makes the comparison
-using @code{eq} instead of @code{equal}.  @code{assq} returns @code{nil}
-if no association in @var{alist} has a @sc{car} @code{eq} to @var{key}.
-This function is used more often than @code{assoc}, since @code{eq} is
-faster than @code{equal} and most alists use symbols as keys.
-@xref{Equality Predicates}.
+using @code{eq}.  @code{assq} returns @code{nil} if no association in
+@var{alist} has a @sc{car} @code{eq} to @var{key}.  This function is
+used more often than @code{assoc}, since @code{eq} is faster than
+@code{equal} and most alists use symbols as keys.  @xref{Equality
+Predicates}.
 
 @smallexample
 (setq trees '((pine . cones) (oak . acorns) (maple . seeds)))