From 0996047476e93f036740c630279629a4c2a825c7 Mon Sep 17 00:00:00 2001 From: Mauro Aranda Date: Tue, 1 Sep 2020 16:59:58 +0200 Subject: [PATCH] Improve documentation for custom :options * doc/lispref/customize.texi (Variable Definitions): Mention that re-evaluating a defcustom form doesn't reset custom options (bug#30101). --- doc/lispref/customize.texi | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/doc/lispref/customize.texi b/doc/lispref/customize.texi index 2a72276bc56..b9c9130a920 100644 --- a/doc/lispref/customize.texi +++ b/doc/lispref/customize.texi @@ -358,6 +358,10 @@ This is meaningful only for certain types, currently including @code{hook}, @code{plist} and @code{alist}. See the definition of the individual types for a description of how to use @code{:options}. +Re-evaluating a @code{defcustom} form with a different @code{:options} +value does not clear the values added by previous evaluations, or +added by calls to @code{custom-add-frequent-value} (see below). + @item :set @var{setfunction} @kindex set@r{, @code{defcustom} keyword} Specify @var{setfunction} as the way to change the value of this @@ -485,6 +489,10 @@ list of reasonable values. The precise effect of adding a value depends on the customization type of @var{symbol}. + +Since evaluating a @code{defcustom} form does not clear values added +previously, Lisp programs can use this function to add values for user +options not yet defined. @end defun Internally, @code{defcustom} uses the symbol property -- 2.39.2