[PATCH] gnu: graphviz: Enable Guile library.

[Roel Janssen]

Dear Guix,

I would like to add graphviz's Guile interface to the package
definition.  This introduces two new (top-level) dependencies to the
graphviz package: guile and swig.

An example of the Guile interface:
(load-extension (string-append (getenv "HOME") 
"/.guix-profile/lib/graphviz/guile/libgv_guile.so") "SWIG_init")

;; Define the graph's nodes and edges.
(define my-graph (graph "G"))
(edge
  (node my-graph "A")
  (node my-graph "B"))

;; Set a lay-out and render it to a file.
(layout my-graph "dot")
(render my-graph "svg" "/home/roel/my-graph.svg")

The patch is fairly straightforward, since all that is needed is include
the dependencies to the inputs:

>From 8e93c01a9c0909f49c4b644c965824fd5f74527a Mon Sep 17 00:00:00 2001
From: Roel Janssen <address@hidden>
Date: Mon, 9 May 2016 11:26:18 +0200
Subject: [PATCH] gnu: graphviz: Enable Guile library.

gnu/packages/graphviz.scm (graphviz): Add inputs to enable the Guile library.
---
 gnu/packages/graphviz.scm | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/gnu/packages/graphviz.scm b/gnu/packages/graphviz.scm
index 09f475b..ddb3e67 100644
--- a/gnu/packages/graphviz.scm
+++ b/gnu/packages/graphviz.scm
@@ -25,6 +25,7 @@
   #:use-module (gnu packages gtk)
   #:use-module (gnu packages xml)
   #:use-module (gnu packages glib)
+  #:use-module (gnu packages guile)
   #:use-module (gnu packages bison)
   #:use-module (gnu packages image)
   #:use-module (gnu packages autotools)
@@ -32,6 +33,7 @@
   #:use-module (gnu packages fontutils)
   #:use-module (gnu packages compression)
   #:use-module (gnu packages gd)
+  #:use-module (gnu packages swig)
   #:use-module ((guix licenses) #:select (lgpl2.0+ epl1.0)))
 
 (define-public graphviz
@@ -75,6 +77,8 @@
        ("libX11" ,libx11)
        ("gts" ,gts)
        ("gd" ,gd)                                 ; FIXME: Our GD is too old
+       ("guile" ,guile-2.0)
+       ("swig" ,swig)
        ("pango" ,pango)
        ("fontconfig" ,fontconfig)
        ("freetype" ,freetype)
-- 
2.7.4


Thank you for your time.

Kind regards,
Roel Janssen