bug#25671: Feature request: emacs -Q --script as a single binary

bug#25671: Feature request: emacs -Q --script as a single binary

[Clément Pit--Claudel]

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Hi bug-gnu-emacs,

Since version 22 Emacs lets scripts begin with a shebang line:

  #!/usr/bin/emacs --script
  ;; Some ELisp code here

This breaks if Emacs isn't installed in /usr/bin, though.  Thus, one would want to write this:

  #!/usr/bin/env emacs --script
  ;; Some ELisp code here

But this doesn't work (env doesn't split its arguments), and it also breaks even if one is happy with hardcoding /usr/bin/emacs but tries to pass more than one argument (think -Q and --script).  Thus one writes this:

  #!/bin/sh
  ":"; exec emacs -Q --script "$0" "$@" # -*- mode: emacs-lisp; lexical-binding: t; -*-

(See http://stackoverflow.com/questions/6238331/emacs-shell-scripts-how-to-put-initial-options-into-the-script/6259330#6259330)

This isn't pretty.  Could we set up emacs to assume --script and possibly -Q when started as "elisp", or "emacs-script", or some other name (that is, could we make it so that invoking emacs with argv[0] = ".../elisp" starts emacs -Q --script)? (And ideally Emacs would ignore all options after the script's name, to let the script itself process them).

Thanks!
Clément.


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bug#25671: Feature request: emacs -Q --script as a single binary

[Glenn Morris]

This seems like a duplicate of https://debbugs.gnu.org/20682 .

(IMO a big, unwieldy text editor that is never going to be a sensible
alternative to bash, perl, python etc for scripting.)

bug#25671: Feature request: emacs -Q --script as a single binary

[Clément Pit--Claudel]

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On 2017-02-09 16:27, Glenn Morris wrote:
> This seems like a duplicate of https://debbugs.gnu.org/20682 .
> 
> (IMO a big, unwieldy text editor that is never going to be a sensible
> alternative to bash, perl, python etc for scripting.)

Partly; thanks for the pointer! That thread still assumes that you can pass an argument to Emacs, though, which isn't always the case (e.g. if you want to use /usr/bin/env).

Clément.


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bug#25671: Feature request: emacs -Q --script as a single binary

[Eli Zaretskii]

> From: Clément Pit--Claudel <clement.pitclaudel@live.com>
> Date: Thu, 9 Feb 2017 16:14:41 -0500
> 
> Could we set up emacs to assume --script and possibly -Q when started as "elisp", or "emacs-script", or some other name (that is, could we make it so that invoking emacs with argv[0] = ".../elisp" starts emacs -Q --script)? (And ideally Emacs would ignore all options after the script's name, to let the script itself process them).

I believe changing the program behavior depending on how it was named
in the command that invoked it is against GNU coding standards.

bug#25671: Feature request: emacs -Q --script as a single binary

[Clément Pit--Claudel]

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On 2017-02-10 02:37, Eli Zaretskii wrote:
>> From: Clément Pit--Claudel <clement.pitclaudel@live.com>
>> Date: Thu, 9 Feb 2017 16:14:41 -0500
>>
>> Could we set up emacs to assume --script and possibly -Q when started as "elisp", or "emacs-script", or some other name (that is, could we make it so that invoking emacs with argv[0] = ".../elisp" starts emacs -Q --script)? (And ideally Emacs would ignore all options after the script's name, to let the script itself process them).
> 
> I believe changing the program behavior depending on how it was named
> in the command that invoked it is against GNU coding standards.

What about providing elisp or emacs-script as a separate binary?


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bug#25671: Feature request: emacs -Q --script as a single binary

[Eli Zaretskii]

> Cc: 25671@debbugs.gnu.org
> From: Clément Pit--Claudel <clement.pitclaudel@live.com>
> Date: Fri, 10 Feb 2017 09:17:00 -0500
> 
> > I believe changing the program behavior depending on how it was named
> > in the command that invoked it is against GNU coding standards.
> 
> What about providing elisp or emacs-script as a separate binary?

What about it?

bug#25671: Feature request: emacs -Q --script as a single binary

[Clément Pit--Claudel]

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On 2017-02-10 10:02, Eli Zaretskii wrote:
>> Cc: 25671@debbugs.gnu.org
>> From: Clément Pit--Claudel <clement.pitclaudel@live.com>
>> Date: Fri, 10 Feb 2017 09:17:00 -0500
>>
>>> I believe changing the program behavior depending on how it was named
>>> in the command that invoked it is against GNU coding standards.
>>
>> What about providing elisp or emacs-script as a separate binary?
> 
> What about it?

Would that be OK? Could it work?  I thought it would make implementation simpler to just make the emacs binary ct differently based on how its invoked, but if that's not OK then could we distribute a separate "elisp" or "emacs-script" binary that can be used in a shebang line?


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bug#25671: Feature request: emacs -Q --script as a single binary

[Eli Zaretskii]

> Cc: 25671@debbugs.gnu.org
> From: Clément Pit--Claudel <clement.pitclaudel@live.com>
> Date: Fri, 10 Feb 2017 11:45:55 -0500
> 
> >>> I believe changing the program behavior depending on how it was named
> >>> in the command that invoked it is against GNU coding standards.
> >>
> >> What about providing elisp or emacs-script as a separate binary?
> > 
> > What about it?
> 
> Would that be OK? Could it work?

Yes, it will.  Although distributing two large binaries might be
overkill.  (All that just to make shell scripts slightly simpler?)

bug#25671: Feature request: emacs -Q --script as a single binary

[Glenn Morris]

Clément Pit--Claudel wrote:

>>> What about providing elisp or emacs-script as a separate binary?
>> 
>> What about it?
>
> Would that be OK?

I would not like installing Emacs to pollute my PATH with trivial things
like that. In https://debbugs.gnu.org/20682#11 I mentioned a
standard solution for this issue as used by perl, ruby, etc;
namely a -x switch.

bug#25671: Feature request: emacs -Q --script as a single binary

[Clément Pit--Claudel]

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On 2017-02-10 12:32, Glenn Morris wrote:
> Clément Pit--Claudel wrote:
> 
>>>> What about providing elisp or emacs-script as a separate binary?
>>>
>>> What about it?
>>
>> Would that be OK?
> 
> I would not like installing Emacs to pollute my PATH with trivial things
> like that. In https://debbugs.gnu.org/20682#11 I mentioned a
> standard solution for this issue as used by perl, ruby, etc;
> namely a -x switch.

Can you explain how that works wrt the problem I mentioned in my original post? "#!/usr/bin/env emacs -x" doesn't work, does it?

Clément


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bug#25671: Feature request: emacs -Q --script as a single binary

[Clément Pit--Claudel]

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On 2017-02-10 11:58, Eli Zaretskii wrote:
>> Cc: 25671@debbugs.gnu.org
>> From: Clément Pit--Claudel <clement.pitclaudel@live.com>
>> Date: Fri, 10 Feb 2017 11:45:55 -0500
>>
>>>>> I believe changing the program behavior depending on how it was named
>>>>> in the command that invoked it is against GNU coding standards.
>>>>
>>>> What about providing elisp or emacs-script as a separate binary?
>>>
>>> What about it?
>>
>> Would that be OK? Could it work?
> 
> Yes, it will.  Although distributing two large binaries might be
> overkill.  (All that just to make shell scripts slightly simpler?)

Right; that's why I thought the "two possible names for the same binary" approach was nice :/
It would make it possible to run elisp command line programs in Windows without a batch script wrapper, and it would make these scripts nicer in GNU/Linux and macOS.  But arguably that's still a limited benefit.  If there's no way to reuse the Emacs binary (that is, if there's no way to make "elisp" just be a wrapper around "emacs"), then I think we should close this issue.

Cheers,
Clément.


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bug#25671: Feature request: emacs -Q --script as a single binary

[Michael Heerdegen]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> > Amazingly, "-x" is available as an Emacs command-line switch...
>
> I think that sounds really attractive, so I've added this to Emacs 29.
> The new -x switch is like --script, but will kill Emacs when it reaches
> the end of the script, and return the value of the final form as the
> return value, so you can say use 0 at the end to signal success to the
> caller.

Thanks - but it doesn't work correctly for me.  Contrarily to --script,
my init file is being loaded with -x.  Does that work correctly for you,
Lars?

TIA,

Michael.