From 5da6be58a0e72a9f7164d8f3a51c2f7f0b3d5155 Mon Sep 17 00:00:00 2001 From: "Richard M. Stallman" Date: Mon, 6 Nov 2006 16:12:15 +0000 Subject: [PATCH] (List Variables): Document COMPARE-FN. --- lispref/lists.texi | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/lispref/lists.texi b/lispref/lists.texi index 62c7600fd17..cf725413895 100644 --- a/lispref/lists.texi +++ b/lispref/lists.texi @@ -713,12 +713,14 @@ l Two functions modify lists that are the values of variables. -@defun add-to-list symbol element &optional append +@defun add-to-list symbol element &optional append compare-fn This function sets the variable @var{symbol} by consing @var{element} onto the old value, if @var{element} is not already a member of that value. It returns the resulting list, whether updated or not. The value of @var{symbol} had better be a list already before the call. -Membership is tested using @code{equal}. +@code{add-to-list} uses @var{compare-fn} to compare @var{element} +against existing list members; if @var{compare-fn} is @code{nil}, it +uses @code{equal}. Normally, if @var{element} is added, it is added to the front of @var{symbol}, but if the optional argument @var{append} is