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From: Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
To: 73853@debbugs.gnu.org
Cc: monnier@iro.umontreal.ca
Subject: bug#73853: 31.0.50; and-let* is useless
Date: Thu, 17 Oct 2024 12:27:39 -0400	[thread overview]
Message-ID: <jwv4j5aeltw.fsf@iro.umontreal.ca> (raw)

Package: Emacs
Version: 31.0.50


According to its docstring, `and-let*` does:

    Bind variables according to VARLIST and conditionally evaluate BODY.
    Like `when-let*', except if BODY is empty and all the bindings
    are non-nil, then the result is the value of the last binding.

IOW the only time it's different from `when-let*` is when BODY is empty,
i.e. its only "feature" compares to `when-let*` is that

    (and-let* (..BINDINGS..
               (last (binding))))

is equivalent to

    (and-let* (..BINDINGS..)
      (binding))

Why would anyone write the first instead of the second, other than out
of masochism?  Can we kill/deprecate this?
[ I think we have too many (if|when|and)-let(*) for our own good: we
  should pick some winners and deprecate the other ones.   ]

I could see a use for something called `and-let(*)` but without a BODY,
for the purpose of remove a level of parens and indentation:

    (and-let*
      (x1 (foo1))
      (x2 (foo2)))

i.s.o

    (and-let*
        ((x1 (foo1))
         (x2 (foo2))))


- Stefan






             reply	other threads:[~2024-10-17 16:27 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-17 16:27 Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors [this message]
2024-10-17 16:40 ` bug#73853: 31.0.50; and-let* is useless Drew Adams via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-10-18  2:11 ` Michael Heerdegen via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-10-18 23:42   ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-10-19  3:50     ` Michael Heerdegen via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-10-19  3:38   ` Sean Whitton

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