bug#24145: [PATCH] gnu: asciidoc: Use local docbook-xsl package.

[Leo Famulari <leo@famulari.name>]

On Wed, Aug 03, 2016 at 11:07:52PM +0200, Tomáš Čech wrote:
> * gnu/packages/documentation.scm(asciidoc): New input docbook-xsl,
>   replace use of online source and prefer docbook-xsl package.

Not having any practical experience with docbook-xsl, I think this
change looks fine, in general.

I think the commit message should be like this:

* gnu/packages/documentation.scm (asciidoc)[inputs]: Add docbook-xsl.
[arguments]: Add 'make-local-docbook-xsl' phase.

That is closer to the GNU Changelog format that we prefer to use.

> +         (add-before
> +             'install 'make-local-docbook-xsl

I think these two lines can collapsed into a single line.

> +           (lambda* (#:key inputs #:allow-other-keys)
> +             (substitute* (find-files "docbook-xsl" ".*\\.xsl$")
> +               (("xsl:import href=\"http://docbook.sourceforge.net/release/xsl/current")
> +                (string-append
> +                 "xsl:import href=\""
> +                 (string-append (assoc-ref inputs "docbook-xsl")
> +                                "/xml/xsl/docbook-xsl-"
> +                                ,(package-version docbook-xsl))))))))))

My limited sense of Scheme style tells me to shift the previous 4 lines
to the right by 1 character.

The function should return #t, since (substitute*) has no defined return
value.