From: Bart Schaefer <schaefer@brasslantern.com>
To: Bart Schaefer <schaefer@brasslantern.com>,
Zsh hackers list <zsh-workers@zsh.org>
Subject: Re: Block comments ala Ray
Date: Sun, 14 Feb 2021 12:15:31 -0800 [thread overview]
Message-ID: <CAH+w=7Yydsx6QMhmKj5V_TX6-0sLKo9nNm3t07fsnhd5SKGj8Q@mail.gmail.com> (raw)
In-Reply-To: <20210213083521.kv3y3qzfnaffflfh@chazelas.org>
On Sat, Feb 13, 2021 at 12:35 AM Stephane Chazelas
<stephane@chazelas.org> wrote:
>
> 2021-02-09 22:05:13 -0800, Bart Schaefer:
> [...]
> > !# This begins a block comment.
> > This is merely rambling.
> > This #! is the last line of the block
> [...]
>
> - those !#, #! look too much like a shebang.
Which actually doesn't matter, because #! isn't special anywhere but
the first line.
> - !# is already histsubst syntax.
Also doesn't matter, this was intended only to operate where history
is disabled anyway.
> - It's also the !# extendedglob
You mean "zero or more occurrences of '!' "? This is another reason I
was only allowing "!#" at the start of a line. Under what
circumstances would you begin a new line with that glob?
> - It's also (POSIXly) invoking the !# command.
Yes, I mentioned that. It seems pretty damn unlikely to use that, as
it has no effect other than to set $? to 1.
> Also consider
> scripts that do:
>
> cat > script <<EOF
> #! /bin/sh -
> ...
> EOF
>
> making it difficult to comment out those codes
That one has some relevance, and argues for requiring #! to be
followed immediately by a newline, if not also preceded by one.
> - syntax is a bit obscure and uncommon.
Intentionally so, yes. It has to be something that would essentially
never appear in an existing script.
> Would we allow blanks
> before the !# for indentation purposes.
No.
> Would those !# be
> recognised if the previous line ends in a \ or inside
> heredocs?
No, because it's handled by the lexer. It's not recognized anywhere
any other comment isn't.
> Does it have to be delimited with whitespace? Can we
> use !########### .. ##############!? That ! is easy to miss.
Those are among the reasons I didn't think forming "inline comments"
was a good idea.
> Would we allow escaping the closing #!? How?
No, because you can't escape anything inside a comment.
> - assuming we allow nesting (which would be useful to comment
> out sections of code that contain block comments),
I hadn't considered nesting. You can't nest C /* ... */ comments, and
this was not intended to work any differently.
> - <<# .. #>> allows inline comments, but looks more like a
> redirection operator than a comment.
That's why I rejected <# ... #>.
> To me, there are more useful features that could be added to zsh
> before that one.
This is like saying we should solve problems on earth before we spend
money on space exploration. It's a false dichotomy.
> Or ksh's <#((...)), <#.. <>; redirection operators.
The possibility of wanting to add those would also argue against using
"<#" or "<<#" as a comment introducer.
next prev parent reply other threads:[~2021-02-14 20:16 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-10 6:05 Bart Schaefer
2021-02-10 6:16 ` Roman Perepelitsa
2021-02-12 6:17 ` Bart Schaefer
2021-02-12 6:26 ` Bart Schaefer
2021-02-12 6:41 ` Roman Perepelitsa
2021-02-12 7:40 ` Stephane Chazelas
2021-02-12 7:46 ` Roman Perepelitsa
2021-02-12 15:30 ` Bart Schaefer
2021-02-12 15:45 ` Stephane Chazelas
2021-02-12 16:55 ` Bart Schaefer
2021-02-12 18:16 ` Lawrence Velázquez
2021-02-12 21:02 ` Stephane Chazelas
2021-02-12 21:12 ` Stephane Chazelas
2021-02-12 21:29 ` Bart Schaefer
2021-02-13 7:37 ` Stephane Chazelas
2021-02-15 22:28 ` Daniel Shahaf
2021-02-13 4:33 ` Bart Schaefer
2021-02-15 0:42 ` Greg Klanderman
2021-02-12 15:24 ` Matthew Martin
2021-02-12 16:18 ` Bart Schaefer
2021-02-15 21:30 ` Daniel Shahaf
2021-02-15 22:35 ` Bart Schaefer
2021-02-12 20:48 ` Bart Schaefer
2021-02-13 8:35 ` Stephane Chazelas
2021-02-13 8:53 ` Stephane Chazelas
2021-02-14 20:50 ` Bart Schaefer
2021-02-14 20:15 ` Bart Schaefer [this message]
2021-02-15 0:36 ` Vincent Lefevre
2021-02-15 1:07 ` Bart Schaefer
2021-02-15 1:38 ` Vincent Lefevre
2021-02-15 17:43 ` Stephane Chazelas
2021-02-15 22:06 ` Daniel Shahaf
2021-02-15 22:39 ` Bart Schaefer
2021-02-14 20:58 ` Bart Schaefer
2021-02-16 15:30 ` Juergen Christoffel
2021-02-16 17:21 ` Vincent Lefevre
2021-02-16 18:29 ` Bart Schaefer
2021-02-16 21:35 ` Juergen Christoffel
2021-02-16 18:21 ` pod documentation in zsh scripts (Was: Block comments ala Ray) Stephane Chazelas
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