Re: [PATCH] Improve shell script headers and pre-inst-env handling

[ludo@gnu.org (Ludovic Courtès)]

Mark H Weaver <mhw@netris.org> skribis:

> So I've been working on a patch to fix the ./pre-inst-env problem using
> portable shell code instead of Guile code, as you suggested, and this is
> the kind of code I'm coming up with:

The first snippet looks good to me.

> but the more I look at this ugly, buggy code; and the more I fret
> about the inherent bugs having to do with poor handling of shell
> meta-characters and colons in file names; and the more I read of the
> "Portable Shell Programming" chapter of the autoconf manual, the less
> I understand why you feel so strongly about using this awful language
> instead of the Guile code I wrote.  To save a few lines?

I think either we mix shell and Scheme (which we more or less have to do
because Guile is largely unusable as a shebang for several reasons), in
which case the shell snippet should be as small as possible, or we do
Scheme-only (which I thought was impossible, but I could be wrong.)

So:

> Please take a look at my proposed code one more time with fresh eyes:

[...]

> startup="
> (let ()
>   (define-syntax-rule (push! elt v) (set! v (cons elt v)))
>   (define (main interpreter module-dir script-file . args)
>     (unless (getenv \"GUIX_UNINSTALLED\")
>       (push! module-dir %load-path)
>       (push! module-dir %load-compiled-path))
>     (load script-file)
>     (let ((proc (module-ref (resolve-interface '($script))
>                             '$script)))
>       (apply proc args)))
>   (apply main (command-line)))

Would this work if we used “#!@GUILE@ -ds” and do that from there?

> * The boilerplate code is identical in all scripts except on line 4
>   (script=guix-build).

Note that I think we’ll most likely have a single ‘guix’ script in the
near future, so that ‘guix-pull’ can actually update everything: Guix,
commands, and distro.

>> (BTW, rather than $GUIX_UNINSTALLED, it just occurred to me that
>> $GUIX_LOAD_PATH would do just as well while being more generic and
>> easier to implement/use.)
>
> I thought about this too, but it seems to me that it wouldn't work
> properly for "./pre-inst-env guile".  Or am I missing something?

Something like:

--8<---------------cut here---------------start------------->8---
GUILE_LOAD_COMPILED_PATH="${GUIX_LOAD_PATH}${GUIX_LOAD_PATH:+:}@guilemoduledir@:$GUILE_LOAD_COMPILED_PATH"
export GUILE_LOAD_COMPILED_PATH
GUILE_LOAD_PATH="${GUIX_LOAD_PATH}${GUIX_LOAD_PATH:+:}@guilemoduledir@:$GUILE_LOAD_PATH"
export GUILE_LOAD_PATH

main='(module-ref (resolve-interface '\''(guix-package)) '\'guix-package')'
exec ${GUILE-@GUILE@} -l "$0" ...
--8<---------------cut here---------------end--------------->8---

Thoughts?  :-)

Ludo’.