def end_rule_definition(self):
"""End defining a rule."""
# Make sure a rule is being defined at the moment.
if not self._current_rule_name:
raise CompilerError("Cannot end defining a rule when" \
" no rule is being defined.")
# Make sure that no other rule has been defined with this name.
if self._current_rule_name in self._rule_definitions:
raise CompilerError("Rule '%s' defined more than once." % \
self._current_rule_name)
# If this rule has not been used before, register it.
if self._current_rule_name not in self._rules:
self._rules.append(self._current_rule_name)
if self._current_rule_export:
self._export_rules.append(self._current_rule_name)
self._rule_definitions[self._current_rule_name] = \
self._current_rule_definition
self._current_rule_name = None
self._current_rule_export = None
self._current_rule_definition = None