GNU bug report logs - #76242
[PATCH] Clarify that mapconcat's FUNCTION can return nil

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From: Michael Heerdegen <michael_heerdegen <at> web.de>
To: 76242 <at> debbugs.gnu.org
Cc: hong <at> topbug.net
Subject: bug#76242: [PATCH] Clarify that mapconcat's FUNCTION can return nil
Date: Thu, 13 Feb 2025 02:27:52 +0100

Hong Xu via "Bug reports for GNU Emacs, the Swiss army knife of text
editors" <bug-gnu-emacs <at> gnu.org> writes:

> -FUNCTION must be a function of one argument, and must return a value
> -  that is a sequence of characters: either a string, or a vector or
> -  list of numbers that are valid character codepoints.  */)
> + FUNCTION must be a function of one argument, and must return either:
> +
> +   nil, which is treated as an empty string, or
> +   a value that is a sequence of characters, which is either a string,
> +   or a vector or list of numbers that are valid character codepoints. */)

I don't understand the rationale.  Isn't nil just one case of an empty
sequence of characters?  Why describe it specially?


Michael.

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