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Subject: |
26.2.90; mapconcat "SEPARATOR must be a string." is incorrect |
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Date: |
Fri, 28 Jun 2019 21:23:24 +0800 |
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User-agent: |
Emacs/26.2.90 |
C-h f mapconcat says
> SEPARATOR must be a string.
but nil works fine
(mapconcat #'identity '("a" "b") nil)
;; => "ab"
and `string-join` relies on this fact (by the way, string-join's
docstring doesn't explain the case when separator is omitted or nil)
(defsubst string-join (strings &optional separator)
"Join all STRINGS using SEPARATOR."
(mapconcat 'identity strings separator))
C-h S mapconcat says
> SEPARATOR, which also must be a string, or a vector or list of
> characters.
C-h f concat says
> Each argument may be a string or a list or vector of characters (integers).
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--- Begin Message ---
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Subject: |
Re: bug#36418: 26.2.90; mapconcat "SEPARATOR must be a string." is incorrect |
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Date: |
Sat, 06 Jul 2019 10:32:51 +0300 |
> From: Stefan Kangas <address@hidden>
> Date: Sat, 6 Jul 2019 06:17:08 +0200
> Cc: address@hidden
>
> > C-h S mapconcat says
> >
> >> SEPARATOR, which also must be a string, or a vector or list of
> >> characters.
> >
> > C-h f concat says
> >
> >> Each argument may be a string or a list or vector of characters (integers).
>
> In other words, since SEPARATOR can be a "list of characters", it
> follows that it can also be nil (which is equivalent to the empty list).
Right, I fixed the doc string.
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