From 66fd2c72334d7db3dfa38c3c7b875ecefa6cdd0f Mon Sep 17 00:00:00 2001 From: "Richard M. Stallman" Date: Tue, 30 Sep 2003 13:00:23 +0000 Subject: [PATCH] (Association Lists): Clarify `assq-delete-all'. --- lispref/lists.texi | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/lispref/lists.texi b/lispref/lists.texi index b437916694f..5042d52d674 100644 --- a/lispref/lists.texi +++ b/lispref/lists.texi @@ -1670,14 +1670,19 @@ the associations of one copy without affecting the other: @defun assq-delete-all key alist @tindex assq-delete-all This function deletes from @var{alist} all the elements whose @sc{car} -is @code{eq} to @var{key}. It returns @var{alist}, modified -in this way. Note that it modifies the original list structure -of @var{alist}. +is @code{eq} to @var{key}, much as if you used @code{delq} to delete +such each element one by one. It returns the shortened alist, and +often modifies the original list structure of @var{alist}. For +correct results, use the return value of @code{assq-delete-all} rather +than looking at the saved value of @var{alist}. @example -(assq-delete-all 'foo - '((foo 1) (bar 2) (foo 3) (lose 4))) +(setq alist '((foo 1) (bar 2) (foo 3) (lose 4))) + @result{} ((foo 1) (bar 2) (foo 3) (lose 4)) +(assq-delete-all 'foo alist) @result{} ((bar 2) (lose 4)) +alist + @result{} ((foo 1) (bar 2) (lose 4)) @end example @end defun -- 2.39.2