def is_valid(rules_text, program_text):
rules = parse_rules(rules_text)
table = ParseTable(rules)
parser = LRParser(rules, table.action_table(), table.goto_table())
try:
derivation = parser.parse(program_text)
except:
return False
return True
def construct_parser(rules_text, is_verbose=False):
def log(msg=""):
if is_verbose:
print(msg)
log("Parsing rules...")
rules = parse_rules(rules_text)
log("\n".join(map(str, rules)))
log()
log("Constructing parse tables...")
table = ParseTable(rules)
log(table)
parser = LRParser(rules, table.action_table(), table.goto_table())
return parser