Re: Emacs script options

[Sebastian Miele <iota@whxvd.name>]

> From: Jens Schmidt <jschmidt4gnu@vodafonemail.de>
> Date: Mon, 2023-11-20 21:10 +0100
>
> On 2023-11-20  07:10, Sebastian Miele wrote:
>
>> But it has a problem with lexical binding.  Consider:
>>
>>   #!/bin/sh
>>   : ; exec emacs --script "$0" -- "$@" #; -*- lexical-binding: t; mode: emacs-lisp -*-
>>
>>   (defmacro lexical-binding-p ()
>>     '(let* ((x t)
>>             (f (lambda () x))
>>             (x nil))
>>        (funcall f)))
>>
>>   (message "%s %s" lexical-binding (lexical-binding-p))
>>
>> When I run it as a script, the output is "nil nil", i.e., the script
>> definitely does not run with lexical binding enabled.  When I evaluate
>> it in a buffer, the output is "t t".
>
> I tried byte-compiling something similar yesterday, which also
> indicated that the byte-compiler compiles with lexical bindings.  Only
> the scripting machinery sees dynamical bindings.
>
> […]  It seems that the scripting machinery expects a semicolon in the
> very first column, without that the lexical-binding line is not
> recognized.  Even a space before the semicolon breaks the recognition.
>
> The problem is in function `lisp_file_lexically_bound_p' from lread.c,
> which is indeed much more strict in its recognition of the -*- ... -*-
> stanza than the functions `set-auto-mode-1' and
> `hack-local-variables-prop-line' from files.el.  The Emacs manual
> ((emacs) Specifying File Variables) only mentions that the stanza
> has to be in the first line (or the second one if the first is taken
> by a she-bang), without any restriction where the comment has to
> start.

Thank you for the additional investigation into and information about
the issue.

> Would you or Greg report that as a bug?

Done, https://debbugs.gnu.org/cgi/bugreport.cgi?bug=67321.