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Re: (guix modules) and ‘source-module-closure’
From: |
Ricardo Wurmus |
Subject: |
Re: (guix modules) and ‘source-module-closure’ |
Date: |
Mon, 5 Sep 2016 10:13:27 +0200 |
User-agent: |
mu4e 0.9.16; emacs 24.5.1 |
Ludovic Courtès <address@hidden> writes:
> Hi!
>
> Commit 7ca87354db53fd1e1a7a3dfeddb9a598ea064bbe adds (guix module),
> which provides a way to compute the closure of a Scheme module by
> looking at its source code.
>
> This has to do with typical ‘with-imported-modules’ usage, as explained
> in the manual:
>
> --8<---------------cut here---------------start------------->8---
> Usually you want the _closure_ of the module to be imported—i.e., the
> module itself and all the modules it depends on—rather than just the
> module; failing to do that, attempts to use the module will fail because
> of missing dependent modules. The ‘source-module-closure’ procedure
> computes the closure of a module by looking at its source file headers,
> which comes in handy in this case:
>
> (use-modules (guix modules)) ;for 'source-module-closure'
>
> (with-imported-modules (source-module-closure
> '((guix build utils)
> (gnu build vm)))
> (gexp->derivation "something-with-vms"
> #~(begin
> (use-modules (guix build utils)
> (gnu build vm))
> ...)))
> --8<---------------cut here---------------end--------------->8---
>
> The benefit can be seen in the next commit:
>
>
> http://git.savannah.gnu.org/cgit/guix.git/commit/?id=239c6e276214813f59f761c9dc5cc0e9d266b49b
Ah, very nice!
Why is it necessary to read the file and parse the define-module
expression? Does Guile not keep any of this information? Should it?
Will something like this become part of Guile eventually?
~~ Ricardo