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Re: Codifying some aspects of Elisp code style and improving pretty prin
From: |
Stefan Monnier |
Subject: |
Re: Codifying some aspects of Elisp code style and improving pretty printer |
Date: |
Fri, 01 Oct 2021 11:26:51 -0400 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) |
> Apropos, I believe the current recommendation is to do
> (mapconcat #'identity seqs " ")
> rather than
> (mapconcat 'identity seqs " ")
> ie function-quoting the argument to mapconcat, apply, mapc etc, but
Indeed, the main benefit being that the byte-compiler can warn you if
the function is not known to be defined (typically because of a typo or
a missing `require`).
A side benefit is that it "does the right thing" for `cl-flet` and friends.
> 1. The elisp manual doesnʼt say that in (info "(elisp) Mapping Functions")
Not sure that'd be the best place, but we should probably adjust the
manual to encourage the use of #' to quote function names,
> 2. Emacs' code itself doesnʼt do that consistently
The difference is sufficiently unimportant that I don't see a need to
try and make it consistent in this respect. E.g. I do change 'foo to
#'foo quite often, but only as part of other changes.
> (and we have the odd #'(lambda ...) as well
I don't see anything wrong with #'(lambda...)
[ I personally prefer to skip the #' to make the code (marginally)
shorter, but it's purely a matter of taste and I usually try and
refrain from making this change in existing code unless it helps make
the code fit into 80 columns. ]
> 3. The byte compiler doesnʼt warn about it.
Mine does ;-)
But I wouldn't want to enable such a warning by default (or at least it
should be mess a bit less eager than it is, because of the occasional false
positives).
> I believe it helps the byte-compiler generate better code, but donʼt
> know what the actual effect is.
It has no effect on the generated code.
Stefan