def __restore_previous_state(self, grammar: Grammar) -> None:
to_remove = set(grammar.get_rules())
for rule in to_remove:
grammar.remove_rule(rule)
self.iteration.remove_crowding_rule(rule)
for rule in self.__last_rules:
grammar.add_rule(rule)
self.iteration.add_rule(rule)
def __replace_all_symbols_in_rules(self, replacement: Symbol,
replaced: Symbol,
grammar: Grammar) -> None:
rules: Set[Rule] = grammar.get_rules()
rules_copy = set(rules)
for rule in rules_copy:
if self.__rule_contains_replaced_symbol(rule, replaced):
new_rule = self.__replace_symbols_in_rule(
replacement, replaced, rule)
grammar.remove_rule(rule)
grammar.add_rule(new_rule)
def split(self, grammar: Grammar) -> None:
replaced: Symbol = self.__find_nonterminal(grammar)
replacement: Tuple[Symbol,
Symbol] = self.__find_unused_symbols_pair(grammar)
print("[split] replaced = {} replacement = {}".format(
replaced, replacement))
if replacement is not None:
rules: Set[Rule] = grammar.get_rules()
rules_copy = set(rules)
for rule in rules_copy:
if rule.left == replaced:
first_rule = self.__create_rule(replacement[0],
rule.right1, rule.right2)
second_rule = self.__create_rule(replacement[1],
rule.right1, rule.right2)
grammar.remove_rule(rule)
grammar.add_rule(first_rule)
grammar.add_rule(second_rule)
self.iteration.remove_crowding_rule(rule)
self.iteration.add_rule(first_rule)
self.iteration.add_rule(second_rule)
rules: Set[Rule] = grammar.get_rules()
rules_copy = set(rules)
for rule in rules_copy:
if rule.right1 == replaced:
grammar.remove_rule(rule)
first_rule = self.__create_rule(rule.left, replacement[0],
rule.right2)
second_rule = self.__create_rule(rule.left, replacement[1],
rule.right2)
grammar.add_rule(first_rule)
grammar.add_rule(second_rule)
self.iteration.remove_crowding_rule(rule)
self.iteration.add_rule(first_rule)
self.iteration.add_rule(second_rule)
rules: Set[Rule] = grammar.get_rules()
rules_copy = set(rules)
for rule in rules_copy:
if rule.right2 == replaced:
first_rule = self.__create_rule(rule.left, rule.right1,
replacement[0])
second_rule = self.__create_rule(rule.left, rule.right1,
replacement[1])
grammar.remove_rule(rule)
grammar.add_rule(first_rule)
grammar.add_rule(second_rule)
self.iteration.remove_crowding_rule(rule)
self.iteration.add_rule(first_rule)
self.iteration.add_rule(second_rule)