Templates: Reorganise default filters

patacrep/songs/chordpro/__init__.py

@@ -14,7 +14,6 @@ from patacrep.songs.chordpro.syntax import parse_song
 from patacrep.songs.errors import FileNotFound, SongUnknownLanguage
 from patacrep.templates import Renderer
 from patacrep.latex import lang2babel, UnknownLanguage
-from patacrep.files import path2posix
 
 LOGGER = logging.getLogger(__name__)
 
@@ -22,6 +21,10 @@ def sort_directive_argument(directives):
     """Sort directives by their argument."""
     return sorted(directives, key=operator.attrgetter("argument"))
 
+DEFAULT_FILTERS = {
+    'sortargs': sort_directive_argument,
+    }
+
 class ChordproSong(Song):
     """Chordpro song parser"""
     # pylint: disable=abstract-method
@@ -41,10 +44,14 @@ class ChordproSong(Song):
             'song': song,
             }
 
-    @staticmethod
-    def _jinja2_filters():
+    def _filters(self):
         """Return additional jinja2 filters."""
-        return {}
+        filters = DEFAULT_FILTERS.copy()
+        filters.update({
+            'search_image': self.search_image,
+            'search_partition': self.search_partition,
+        })
+        return filters
 
     def render(self, template="song"): # pylint: disable=arguments-differ
         context = {
@@ -59,11 +66,7 @@ class ChordproSong(Song):
         jinjaenv = Environment(loader=FileSystemLoader(
             self.iter_datadirs("templates", "songs", "chordpro", self.output_language)
             ))
-        jinjaenv.filters['search_image'] = self.search_image
-        jinjaenv.filters['search_partition'] = self.search_partition
-        jinjaenv.filters['sortargs'] = sort_directive_argument
-        jinjaenv.filters['path2posix'] = path2posix
-        jinjaenv.filters.update(self._jinja2_filters())
+        jinjaenv.filters.update(self._filters())
 
         try:
             return Renderer(
@@ -132,10 +135,12 @@ class Chordpro2LatexSong(ChordproSong):
             LOGGER.warning(message)
             return None
 
-    def _jinja2_filters(self):
-        return {
+    def _filters(self):
+        parent = super()._filters()
+        parent.update({
             'lang2babel': self.lang2babel,
-            }
+            })
+        return parent
 
     def lang2babel(self, lang):
         """Return the LaTeX babel code corresponding to `lang`.

patacrep/templates.py

@@ -45,6 +45,18 @@ _VARIABLE_REGEXP = re.compile(
     """,
     re.VERBOSE|re.DOTALL)
 
+def _escape_tex(value):
+    '''Escape TeX special characters'''
+    newval = value
+    for pattern, replacement in _LATEX_SUBS:
+        newval = pattern.sub(replacement, newval)
+    return newval
+
+DEFAULT_FILTERS = {
+    "escape_tex": _escape_tex,
+    "iter_datadirs": files.iter_datadirs,
+    "path2posix": files.path2posix,
+    }
 
 class VariablesExtension(Extension):
     """Extension to jinja2 to silently ignore variable block.
@@ -62,14 +74,6 @@ class VariablesExtension(Extension):
         return nodes.Const("") # pylint: disable=no-value-for-parameter
 
 
-def _escape_tex(value):
-    '''Escape TeX special characters'''
-    newval = value
-    for pattern, replacement in _LATEX_SUBS:
-        newval = pattern.sub(replacement, newval)
-    return newval
-
-
 class Renderer:
     """Render a template to a LaTeX file."""
     # pylint: disable=too-few-public-methods
@@ -85,22 +89,23 @@ class Renderer:
         self.jinjaenv.comment_start_string = '(% comment %)'
         self.jinjaenv.comment_end_string = '(% endcomment %)'
         self.jinjaenv.line_comment_prefix = '%!'
-        self.jinjaenv.filters['escape_tex'] = _escape_tex
         self.jinjaenv.trim_blocks = True
         self.jinjaenv.lstrip_blocks = True
-        self._fill_filters()
-        self.template = self.jinjaenv.get_template(template)
-
-    def _fill_filters(self):
-        """Define some jinja2 filters, if not set yet."""
-        for key, value in [
-                ("path2posix", files.path2posix),
-                ("iter_datadirs", files.iter_datadirs),
-                ("lang2babel", self.lang2babel),
-            ]:
+        # Fill default filters
+        for key, value in self.filters().items():
             if key not in self.jinjaenv.filters:
                 self.jinjaenv.filters[key] = value
 
+        self.template = self.jinjaenv.get_template(template)
+
+    def filters(self):
+        """Return a dictionary of jinja2 filters."""
+        filters = DEFAULT_FILTERS.copy()
+        filters.update({
+            "lang2babel": self.lang2babel,
+            })
+        return filters
+
     def lang2babel(self, lang):
         """Return the LaTeX babel code corresponding to `lang`.