Re: Installing a wrapper guile script in <out>/bin

[elaexuotee--- via "Development of GNU Guix and the GNU System distribution." <guix-devel@gnu.org>]

Maxime Devos <maximedevos@telenet.be> wrote:
> Let's presume the binary is called $X.
> 
> What I would do: add a build phase after the "install" phase that renames
> <out>/bin/$X to <out>/bin/.$X-real using the rename-file procedure.  Create
> your wrapper script at <out>/bin/.$X-real with call-with-output-file, some
> I/O procedures and chmod (to make the wrapper script executable).
> 
> I hope that helps, Maxime.

Thanks for the pointers.

The script contents are not what I'm confused about. I don't know how to turn
my gexp script into a file under <out>/bin/. This is conceptually what I want:

    (package
      (name "foo")
      ...
      (arguments
       `(...
         #:phases
         (modify-phases %standard-phases
         ...
         (replace 'install
           (lambda* (#:key outputs #:allow-other-keys)
             (let ((out (assoc-ref outputs "out"))
                   (wrapper-script #~(...)))
             ... ; Do normal install stuff
             (copy-file wrapper-script (string-append out "/bin/foo"))
             ... ; Finish install stuff
             )))))))

Of course `copy-file` doesn't work here because `wrapper-script` is a gexp not
a file. What code do I replace this with?

I am vaguely aware things like `build-expression->derivation` to reify a gexp
into a derivation; however, I'm not sure what to do with the derivation object
in this case or if this is even on the right track.

Cheers!