def _compile_impossible(self, element, *args, **kwargs):
# Override this to avoid VoidRefs disabling entire rules/grammars.
# Use a special <_impossible> private rule instead. Only add the
# special rule if it isn't in the result grammar.
grammar = args[0]
if "_impossible" not in grammar.rule_names:
# Check that the impossible literal contains only valid words.
words = set(self.impossible_literal.split())
valid_literal = bool(words)
for word in words:
if not valid_literal:
break
if not self.engine.check_valid_word(word):
valid_literal = False
if valid_literal:
expansion = jsgf.Literal(self.impossible_literal)
else:
# Fallback on a NullRef. There are some problems with using
# these, but they get the job done for simple rules.
expansion = jsgf.NullRef()
grammar.add_rule(
jsgf.Rule(name="_impossible",
visible=False,
expansion=expansion))
return jsgf.NamedRuleRef("_impossible")
def translate_rule_ref(self, state):
"""
Translate the dragonfly RuleRef object inside the TranslationState
object by collecting all of the rules as necessary using the
'dependencies' list.
:type state: TranslationState
:return TranslationState
"""
element = state.element
if not isinstance(element, RuleRef):
raise TranslationError("Cannot translate element '%s' as a "
"RuleRef." % state.element)
name = element.name
if name not in state.rule_names:
# Make a new equivalent JSGF rule
state.element = element.rule.element
self.get_jsgf_equiv(state)
rule_expansion = state.expansion
new_rule = jsgf.Rule(name, element.rule.exported, rule_expansion)
state.element = element
state.dependencies.append(new_rule)
state.expansion = jsgf.RuleRef(new_rule)
else:
# Use the existing rule
index = state.rule_names.index(name)
state.expansion = jsgf.RuleRef(state.dependencies[index])
return state
def test_using_rule_ref(self):
rule1 = Rule("rule", Literal("hello"), exported=True)
rule_ref = RuleRef(rule1, name="rule_ref")
state = TranslationState(rule_ref)
self.translator.translate_rule_ref(state)
self.assertEqual(state.element, rule_ref)
expected_jsgf_rule = jsgf.Rule("rule_ref", True, "hello")
self.assertListEqual(state.dependencies, [expected_jsgf_rule])
self.assertEqual(state.expansion, jsgf.RuleRef(expected_jsgf_rule))
def compile_rule(self, rule, *args, **kwargs):
return jsgf.Rule(name=self.get_reference_name(rule),
visible=rule.exported,
expansion=self.compile_element(
rule.element, *args, **kwargs))
def translate_to_rule(self, rule_name, df_spec, visible=True):
expansion = self.translate(df_spec).expansion
return jsgf.Rule(rule_name, visible, expansion)