Fix case where configuration file contain no content keyword at all

songbook_core/build.py

@@ -99,7 +99,7 @@ class Songbook(object):
                 )
 
         context = self.build_config(renderer.get_variables())
-        self.contentlist = content.process_content(self.config['content'], context)
+        self.contentlist = content.process_content(self.config.get('content', []), context)
         context['render_content'] = content.render_content
         context['titleprefixkeys'] = ["after", "sep", "ignore"]
         context['content'] = self.contentlist

songbook_core/content/__init__.py

@@ -101,6 +101,8 @@ def render_content(context, content):
 def process_content(content, config = None):
     contentlist = []
     plugins = load_plugins()
+    if not content:
+        content = [["song"]]
     for elem in content:
         if isinstance(elem, basestring):
             elem = ["song", elem]