From: Michael Heerdegen <michael_heerdegen@web.de>
To: Richard Stallman <rms@gnu.org>
Cc: mvoteiza@udel.edu, Stefan Monnier <monnier@IRO.UMontreal.CA>,
emacs-devel@gnu.org
Subject: Re: [Emacs-diffs] master 4612b2a 1/2: Implement and-let*
Date: Thu, 14 Sep 2017 17:46:45 +0200 [thread overview]
Message-ID: <87y3phcmfu.fsf@web.de> (raw)
In-Reply-To: <E1dsAhX-0001B5-4R@fencepost.gnu.org> (Richard Stallman's message of "Wed, 13 Sep 2017 12:39:47 -0400")
Richard Stallman <rms@gnu.org> writes:
> > > (internal--build-binding-value-form): Extend to account for
> > > solitary symbols and (EXPR) items in binding varlist.
>
> > We're forced to accept those forms in `let` and `let*` for historical
> > reasons,
>
> It is not just a matter of history.
> Those are very convenient in 'let'.
> It would be a bad idea not to have them.
> Whether they are useful in other new constructs, I don't know.
> What do these new constructs look like?
Just search for SRFI 2, e.g.
https://www.gnu.org/software/guile/manual/html_node/SRFI_002d2.html
`if-let*' and `when-let*' in Emacs are analogue.
I don't know much about Lisp's history, but I think there was a
misunderstanding about what these special binding forms mean. For
example, making a binding form consisting of a single symbol mean "bind
the symbol to nil" would not make sense in these new constructs -
instead, we test the symbol's value for nilness.
Michael.
prev parent reply other threads:[~2017-09-14 15:46 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20170912171813.26498.77867@vcs0.savannah.gnu.org>
[not found] ` <20170912171815.13B9520DE6@vcs0.savannah.gnu.org>
2017-09-12 17:21 ` [Emacs-diffs] master 4612b2a 1/2: Implement and-let* Stefan Monnier
2017-09-12 17:29 ` Mark Oteiza
2017-09-13 16:39 ` Richard Stallman
2017-09-14 15:46 ` Michael Heerdegen [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://www.gnu.org/software/emacs/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87y3phcmfu.fsf@web.de \
--to=michael_heerdegen@web.de \
--cc=emacs-devel@gnu.org \
--cc=monnier@IRO.UMontreal.CA \
--cc=mvoteiza@udel.edu \
--cc=rms@gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.savannah.gnu.org/cgit/emacs.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).