Re: Reusing code for a build-phase?

[Csepp <raingloom@riseup.net>]

Hartmut Goebel <h.goebel@crazy-compilers.com> writes:

> Hi,
>
> I'm currently packaging vagrant and some plugins. For all plugins an additional phase is required, generating a json file, see below. Since this is quite
> some code, I'd like to put it into some definition or some wrapper. Since it uses (this-package-verion), my attempts failed.
>
> At best, a plugin would then be defined like
>
>   (define-public vagrant-abc (vagrant-plugin-wrapper (package …
>
> Anyhow I'd be happy to when being able to use some function in the phase instead of duplicating the code.
>
> Any ideas? Many thanks in advance
>
>     (arguments
>      (list
>       #:tests? #f ; tests involve running vagrant and downloading a box
>       #:phases
>       #~(modify-phases %standard-phases
>           (add-after 'install 'install-plugin.json
>             (lambda _
>               (let* ((plugins.d (string-append
>                                  #$output "/share/vagrant-plugins/plugins.d"))
>                      (plugin.json (string-append
>                                    plugins.d "/" #$name ".json")))
>                 (mkdir-p plugins.d)
>                 #$(with-extensions (list guile-json-4)
>                     #~(begin
>                         (use-modules (json))
>                         (call-with-output-file plugin.json
>                           (lambda (port)
>                             (scm->json
>                              '((#$name
>                                 .
>                                 (("ruby_version"
>                                   . #$(package-version (this-package-input "ruby")))
>                                  ("vagrant_version"
>                                   . #$(package-version (this-package-input "vagrant")))
>                                  ("gem_version" .  "")
>                                  ("require" . "")
>                                  ("sources" . #()))))
>                              port)))))))))))

Maybe you could create a build system that inherits from the one these
packages use, but adds the extra phase.