gnu: Add dot2tex.

* gnu/packages/graphviz.scm (dot2tex): New variable.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

gnu/packages/graphviz.scm

@@ -5,6 +5,7 @@
 ;;; Copyright © 2017 Ricardo Wurmus <rekado@elephly.net>
 ;;; Copyright © 2017 Tobias Geerinckx-Rice <me@tobias.gr>
 ;;; Copyright © 2017 Gábor Boskovits <boskovits@gmail.com>
+;;; Copyright © 2018 Mathieu Lirzin <mthl@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -43,6 +44,7 @@
   #:use-module (gnu packages gd)
   #:use-module (gnu packages swig)
   #:use-module (gnu packages python)
+  #:use-module (gnu packages tex)
   #:use-module ((guix licenses) #:prefix license:))
 
 (define-public graphviz
@@ -239,3 +241,36 @@ graphs in Graphviz's DOT language, written in pure Python.")
 
 (define-public python2-pydot
   (package-with-python2 python-pydot))
+
+(define-public dot2tex
+  (package
+    (name "dot2tex")
+    (version "2.9.0")
+    (source (origin
+              (method url-fetch)
+              (uri (pypi-uri "dot2tex" version))
+              (sha256
+               (base32
+                "0jhdwp0wv2h0xb7j2s5xiv7i8yaqgfpwwqcyrjvaxkfwsynm8gkx"))))
+    (build-system python-build-system)
+    (arguments
+     `(#:python ,python-2))
+    (inputs
+     `(("texlive-latex-preview" ,texlive-latex-preview)
+       ("graphviz" ,graphviz)))
+    (propagated-inputs
+     `(("python-pyparsing" ,python2-pyparsing)))
+    (home-page "https://github.com/kjellmf/dot2tex")
+    (synopsis "Graphviz to LaTeX converter")
+    (description
+     "The purpose of @code{dot2tex} is to give graphs generated by Graphviz a
+more LaTeX friendly look and feel.  This is accomplished by converting
+@code{xdot} output from Graphviz to a series of PSTricks or PGF/TikZ commands.
+This approach allows:
+
+@itemize @bullet
+@item Typesetting labels with LaTeX, allowing mathematical notation
+@item Using native PSTricks and PGF/TikZ commands for drawing arrows
+@item Using backend specific styles to customize the output
+@end itemize")
+    (license license:expat)))