def check_program_validity(self):
self.current_grammar = program_grammar
self.set_number_of_priorities_level()
try:
self.iterate_over_statement()
except custom_exception.ParsingException:
raise custom_exception.ParsingException(err_const.PROGRAM_PARSING_FAILED)
def token_is_opening_stmt(self):
if self.current_tokens[self.token_index] in OPENING_STMT:
try:
if self.current_tokens[self.token_index + 1] not in CLOSING_STMT:
self.opening_stmt_indexes.append(self.token_index + 1)
else:
self.token_index += 1
except IndexError:
raise custom_exception.ParsingException(err_const.STMT_PARSING_FAILED)
elif self.current_tokens[self.token_index] in CLOSING_STMT:
self.closing_stmt_index = self.token_index
self.iterate_over_inner_statement()
def token_is_opening_stmt(self):
opening_stmt = STATEMENT_PAIRS.keys()
if self.current_tokens[self.token_index] in opening_stmt:
current_token = self.current_tokens[self.token_index]
try:
self.stmt_longer_than_two_tokens(current_token)
except IndexError:
raise custom_exception.ParsingException(
err_const.STMT_PARSING_FAILED)
elif self.current_tokens[self.token_index] in STATEMENT_PAIRS.values():
self.closing_stmt_index = self.token_index
self.iterate_over_inner_statement()
def check_program_validity(self):
if len(self.current_statement
) == 1 and self.current_statement[0] is const.BLOCK_STMT:
return
self.current_grammar = program_grammar
self.set_number_of_priorities_level()
self.current_priority_level = 0
try:
self.reduce_program()
except custom_exception.ParsingException:
raise custom_exception.ParsingException(
err_const.PROGRAM_PARSING_FAILED)
def handle_failed_stmt_reduction(self):
if self.statement_already_recalled:
raise custom_exception.ParsingException(err_const.STMT_PARSING_FAILED)
self.current_grammar = program_grammar
self.set_number_of_priorities_level()
try:
self.iterate_over_statement()
except custom_exception.ParsingException:
self.statement_already_recalled = True
self.current_grammar = statement_grammar
self.set_number_of_priorities_level()
self.current_tokens[self.current_index:self.closing_stmt_index] = self.current_statement
self.token_index -= len(self.current_tokens[self.current_index + 1:self.closing_stmt_index])
def reduce_and_handle_error(self):
is_valid_statement = False
index = 0
while index < len(self.current_statement):
possible_production_rules = self._get_possible_production_rules(
self.current_statement[-(index + 1)])
matching_production = self._find_matching_production(index, possible_production_rules)
if matching_production is not None:
self._replace_current_tokens(index, matching_production)
self.current_priority_level = 0
if len(self.current_statement) > MAX_FINAL_STATEMENT_LENGTH:
self.reduce_and_handle_error()
is_valid_statement = True
index += 1
if not is_valid_statement and self.current_priority_level == (self.number_of_priorities - 1):
raise custom_exception.ParsingException(err_const.STMT_PARSING_FAILED)
def iterate_over_stmt(self):
self.program_grammar_applied = False
self.stmt_grammar_applied = False
self.is_valid_stmt = False
try:
while self.is_valid_stmt is False:
self.current_priority_level = 0
while self.current_priority_level < self.number_of_priorities:
self.reduce_and_handle_error()
self.current_priority_level += 1
if len(self.current_statement
) == MAX_FINAL_STATEMENT_LENGTH:
break
if self.no_math_in_last_two_reductions():
self.switch_grammar()
elif not self.is_valid_stmt:
raise custom_exception.ParsingException(
err_const.STMT_PARSING_FAILED)
except custom_exception.ParsingException:
raise
