From mboxrd@z Thu Jan  1 00:00:00 1970
From: ludo@gnu.org (Ludovic =?utf-8?Q?Court=C3=A8s?=)
Subject: Re: [PATCH 5/6] gnu: Add lua5.2-lpeg.
Date: Thu, 26 Jan 2017 19:01:06 +0100
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References: <20170124144015.24473-1-ricardo.wurmus@mdc-berlin.de>
	<20170124144015.24473-5-ricardo.wurmus@mdc-berlin.de>
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In-Reply-To: <20170124144015.24473-5-ricardo.wurmus@mdc-berlin.de> (Ricardo
	Wurmus's message of "Tue, 24 Jan 2017 15:40:14 +0100")
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To: Ricardo Wurmus <ricardo.wurmus@mdc-berlin.de>
Cc: guix-devel@gnu.org

Ricardo Wurmus <ricardo.wurmus@mdc-berlin.de> skribis:

> * gnu/packages/lua.scm (lua5.2-lpeg): New variable.

I think you didn=E2=80=99t get feedback on this one.

> +(define-public lua5.2-lpeg
> +  (package (inherit lua-lpeg)
> +    (name "lua5.2-lpeg")
> +    (arguments
> +     `(#:phases
> +       (modify-phases %standard-phases
> +         (delete 'configure)
> +         ;; `make install` isn't available, so we have to do it manually
> +         (replace 'install
> +           (lambda* (#:key outputs #:allow-other-keys)
> +             (let ((out (assoc-ref outputs "out"))
> +                   (lua-version ,(version-major+minor (package-version l=
ua-5.2))))
> +               (install-file "lpeg.so"
> +                             (string-append out "/lib/lua/" lua-version))
> +               (install-file "re.lua"
> +                             (string-append out "/share/lua/" lua-versio=
n))

It would be best to avoid duplicating this phase since the only
difference is the version number.  However, this is currently
inconvenient, so it=E2=80=99s probably fine to keep it, with an =E2=80=9CXX=
X=E2=80=9D comment.

To fix it, we=E2=80=99d have to arrange for the phase to stand alone as opp=
osed
to getting the Lua version number from the =E2=80=9Chost side=E2=80=9D.  So=
 it would be
written along the lines of:

  (lambda =E2=80=A6
    (let* ((lua (assoc-ref inputs "lua"))
           (lua-version (extract-version lua)))
      =E2=80=A6))

The Python stuff uses a similar pattern.  The =E2=80=98extract-version=E2=
=80=99 thing is
necessarily hacky and brittle though.

Alternately, we could pass the info as an environment variable,
something that=E2=80=99s not done anywhere yet.

Ludo=E2=80=99.