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From: ludo@gnu.org (Ludovic =?utf-8?Q?Court=C3=A8s?=)
Subject: Re: Using a function as build-step?
Date: Mon, 05 Sep 2016 23:01:55 +0200
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References: <0b8f97f5-d931-a344-1000-8ab64233f026@goebel-consult.de>
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In-Reply-To: <0b8f97f5-d931-a344-1000-8ab64233f026@goebel-consult.de> (Hartmut
	Goebel's message of "Sat, 3 Sep 2016 20:22:37 +0200")
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To: Hartmut Goebel <h.goebel@goebel-consult.de>
Cc: Guix-devel <guix-devel@gnu.org>

Hi!

Hartmut Goebel <h.goebel@goebel-consult.de> skribis:

> while packaging some java apache common packages, I found myself adding
> some build steps over and over again, like this one:
>
>          (replace 'install
>            (lambda* (#:key outputs #:allow-other-keys)
>              (let ((share (string-append (assoc-ref outputs "out")
>                                          "/share/java")))
>                (for-each (=CE=BB (f) (install-file f share))
>                          (find-files "target" "\\.jar$")))))
>
> Now I tried replacing this by a simple line like
>
>          (add-after 'install 'install-javadocs install-javadocs)
>
> and of course some function:
>
>   (define* (install-javadoc #:key outputs #:allow-other-keys)
>     (let ((docs (string-append (assoc-ref outputs "doc")
>                                "/share/doc/" ,name "-" ,version "/")))
>       (mkdir-p docs)
>       (copy-recursively "target/apidocs" docs)
>       ))

Note that the commas here (aka. =E2=80=9Cunquote=E2=80=9D) mean that this e=
xpression
must be enclosed in a ` (aka. =E2=80=9Cquasiquote=E2=80=9D).  See
<https://www.gnu.org/software/guile/manual/html_node/Expression-Syntax.html=
#Expression-Syntax>.

> I did not manage this - not even if not using "name" and "version" and
> not using any function parameters.
>
> What is the correct code?

Like David, I would suggest creating a build-side module, say, (guix
build java-utils), or maybe augmenting (guix build ant-build-system),
and putting =E2=80=98install-javadoc=E2=80=99 in there (Ricardo?).

The code in there will not be in a quasiquote context, so you won=E2=80=99t=
 be
able to use =E2=80=9C,name=E2=80=9D and =E2=80=9C,version=E2=80=9D to get a=
t the package name and
version.

Instead, you could use =E2=80=98package-name->name+version=E2=80=99 from (g=
uix build
utils):

  (define* (install-javadoc #:key outputs =E2=80=A6)
    (let ((out (assoc-ref outputs "out")))
      (call-with-values
          (lambda ()
            (package-name->name+version (strip-store-file-name out)))
        (lambda (name version)
          =E2=80=A6))))

HTH!

Ludo=E2=80=99.