Re-allow macro-only bzl, fix runtime failure. (#37)

This patch:
 - fixes the use of undeclared attributes introduced by b14ff10.
 - allows doc for macro-only bzl to be emitted.

skydoc/main.py

@@ -133,14 +133,15 @@ class MarkdownWriter(object):
 
   def __init__(self, writer_options):
     self.__options = writer_options
+    self.__env = _create_jinja_environment(self.__options.link_ext)
 
   def write(self, rulesets):
     """Write the documentation for the rules contained in rulesets."""
     try:
       temp_dir = tempfile.mkdtemp()
       output_files = []
       for ruleset in rulesets:
-        if len(ruleset.rules) > 0:
+        if not ruleset.empty():
           output_files.append(self._write_ruleset(temp_dir, ruleset))
       if self.__options.overview:
         output_files.append(self._write_overview(temp_dir, rulesets))
@@ -168,8 +169,7 @@ def write(self, rulesets):
 
   def _write_ruleset(self, output_dir, ruleset):
     # Load template and render Markdown.
-    env = _create_jinja_environment(self.__options.link_ext)
-    template = env.get_template('markdown.jinja')
+    template = self.__env.get_template('markdown.jinja')
     out = template.render(ruleset=ruleset)
 
     # Write output to file. Output files are created in a directory structure
@@ -187,10 +187,10 @@ def _write_overview(self, output_dir, rulesets):
     template = self.__env.get_template('markdown_overview.jinja')
     out = template.render(rulesets=rulesets)
 
-    output_file = "%s/%s.md" % (output_dir, self.options.overview_filename)
+    output_file = "%s/%s.md" % (output_dir, self.__options.overview_filename)
     with open(output_file, "w") as f:
       f.write(out)
-    return (output_file, "%s.md" % self.options.overview_filename)
+    return (output_file, "%s.md" % self.__options.overview_filename)
 
 class HtmlWriter(object):
   """Writer for generating documentation in HTML."""
@@ -211,7 +211,7 @@ def write(self, rulesets):
       temp_dir = tempfile.mkdtemp()
       output_files = []
       for ruleset in rulesets:
-        if len(ruleset.rules) > 0:
+        if not ruleset.empty():
           output_files.append(self._write_ruleset(temp_dir, ruleset, nav))
       if self.__options.overview:
         output_files.append(self._write_overview(temp_dir, rulesets, nav))

skydoc/rule.py

@@ -165,3 +165,9 @@ def __init__(self, bzl_file, language, title, description, strip_prefix,
       else:
         assert rule_proto.type == build_pb2.RuleDefinition.REPOSITORY_RULE
         self.repository_rules.append(definition)
+
+  def empty(self):
+    """Return True if there is nothing to document."""
+    return not any([self.rules,
+                    self.macros,
+                    self.repository_rules])

skydoc/templates/toc.jinja

@@ -14,13 +14,31 @@ See the License for the specific language governing permissions and
 limitations under the License.
 #}
 <nav class="toc">
-  <h2>Rules</h2>
-  <ul>
 % if ruleset.description:
-    <li><a href="#overview">Overview</a></li>
+  <h2><a href="#overview">Overview</a></h2>
+% endif
+% if ruleset.repository_rules[0] is defined:
+  <h2>Repository Rules</h2>
+  <ul>
+% for rule in ruleset.repository_rules:
+    <li><a href="#{{ rule.name }}">{{ rule.name }}</a></li>
+% endfor
+  </ul>
 % endif
+% if ruleset.rules[0] is defined:
+  <h2>Rules</h2>
+  <ul>
 % for rule in ruleset.rules:
     <li><a href="#{{ rule.name }}">{{ rule.name }}</a></li>
 % endfor
   </ul>
+% endif
+% if ruleset.macros[0] is defined:
+  <h2>Macros</h2>
+  <ul>
+% for macro in ruleset.macros:
+    <li><a href="#{{ macro.name }}">{{ macro.name }}</a></li>
+% endfor
+  </ul>
+% endif
 </nav>