From 315915221ce241c4b7f6848fb360c48590c974e1 Mon Sep 17 00:00:00 2001
From: Louis <spalax@gresille.org>
Date: Mon, 16 Jun 2014 07:34:55 +0200
Subject: [PATCH] Added \obeylines command to verse, verse* and chorus
 environments.

---
 songbook_core/data/latex/songs_minimal.sty |  8 ++++++
 songbook_core/errors.py                    | 12 ++++++++
 songbook_core/plastex.py                   | 32 +++++++++++++++++++---
 3 files changed, 48 insertions(+), 4 deletions(-)
 create mode 100644 songbook_core/data/latex/songs_minimal.sty

diff --git a/songbook_core/data/latex/songs_minimal.sty b/songbook_core/data/latex/songs_minimal.sty
new file mode 100644
index 00000000..7c3b8a51
--- /dev/null
+++ b/songbook_core/data/latex/songs_minimal.sty
@@ -0,0 +1,8 @@
+% Minimal songs.sty package, to be loaded by the songbook_core library, by the
+% PlasTeX packages. Some songs.sty commands are implemented in Python, in the
+% songbook_core/plastex*.py packages, and some commands are implemented in this
+% file.
+
+\newenvironment{chorus}{\obeylines}{}
+\newenvironment{verse}{\obeylines}{}
+\newenvironment{verse*}{\obeylines}{}
diff --git a/songbook_core/errors.py b/songbook_core/errors.py
index b8e73466..27b15775 100644
--- a/songbook_core/errors.py
+++ b/songbook_core/errors.py
@@ -85,3 +85,15 @@ class UnknownStep(SongbookError):
     def __str__(self):
         return """Compilation step "{step}" unknown.""".format(step=self.step)
 
+
+class LatexImportError(SongbookError):
+    """Could not import package."""
+
+    def __init__(self, package):
+        super(LatexImportError, self).__init__()
+        self.package = package
+
+    def __str__(self):
+        return """Error while importing LaTeX package "{}".""".format(
+                self.package
+                )
diff --git a/songbook_core/plastex.py b/songbook_core/plastex.py
index b743bd00..0d4e14eb 100644
--- a/songbook_core/plastex.py
+++ b/songbook_core/plastex.py
@@ -11,6 +11,9 @@ import locale
 import os
 import sys
 
+from songbook_core import __DATADIR__
+from songbook_core import errors
+
 
 def process_unbr_spaces(node):
     r"""Replace '~' and '\ ' in node by nodes that
@@ -49,16 +52,37 @@ class SongParser(object):
     """Analyseur syntaxique de fichiers .sg"""
 
     @staticmethod
-    def create_tex():
+    def load_package(tex, package):
+        """Wrapper to 'tex.ownerDocument.context.loadPackage' catching errors.
+        """
+        if not tex.ownerDocument.context.loadPackage(tex, package):
+            raise errors.LatexImportError(package)
+
+    @classmethod
+    def create_tex(cls):
         """Create a TeX object, ready to parse a tex file."""
         tex = TeX()
         tex.disableLogging()
         tex.ownerDocument.context.loadBaseMacros()
+
+        # Setting paths
         sys.path.append(os.path.dirname(__file__))
-        tex.ownerDocument.context.loadPackage(tex, "plastex_patchedbabel")
-        tex.ownerDocument.context.loadPackage(tex, "plastex_chord")
-        tex.ownerDocument.context.loadPackage(tex, "plastex_songs")
+        old_texinputs = os.environ.get("TEXINPUTS", '')
+        os.environ["TEXINPUTS"] = "{}:{}".format(
+                old_texinputs,
+                os.path.join(__DATADIR__, "latex"),
+                )
+
+        # Loading packages
+        cls.load_package(tex, "plastex_patchedbabel")
+        cls.load_package(tex, "plastex_chord")
+        cls.load_package(tex, "plastex_songs")
+        cls.load_package(tex, "songs_minimal.sty")
+
+        # Unsetting paths
         sys.path.pop()
+        os.environ["TEXINPUTS"] = old_texinputs
+
         return tex
 
     @classmethod