regex = None
method = None
while opt != 0:
print(main_menu)
opt = input('> ')
if opt == '1':
print(type_regex_msg)
regex = input('> ')
try:
reader = Reader(regex)
tokens = reader.CreateTokens()
parser = Parser(tokens)
tree = parser.Parse()
direct_reader = DirectReader(regex)
direct_tokens = direct_reader.CreateTokens()
direct_parser = Parser(direct_tokens)
direct_tree = direct_parser.Parse()
print('\n\tExpression accepted!')
print('\tParsed tree:', tree)
except AttributeError as e:
print(f'\n\tERR: Invalid expression (missing parenthesis)')
except Exception as e:
print(f'\n\tERR: {e}')
if opt == '2':
