def __init__(self, filename):
self.scanner = Scanner(filename)
self.current_token = None
self.current_word = None
class Parser(object):
_symbols = dict(SYMBOLS)
_reserved_words = dict(reserved_words)
def __init__(self, filename):
self.scanner = Scanner(filename)
self.current_token = None
self.current_word = None
@staticmethod
def _is_valid_identifier(var_name):
if not var_name:
return False
return var_name[0].isalpha() and var_name.isalnum()
def get_next_token(self):
self.current_word = self.scanner.get_word().lower()
self.current_token = self._lookup_token(self.current_word)
return self.current_token
def _lookup_token(self, word):
if not word:
return None
token = self._get_double_symbol(word)
if token:
return token
token = self._symbols.get(word, None) or self._reserved_words.get(word, None)
if token:
return token
if word.isdigit():
return TK_A_DIGIT
if word in ['true', 'false']:
return TK_A_BOOL
if self._is_valid_identifier(word):
return TK_IDENTIFIER
return ''
def _get_double_symbol(self, word):
if word in double_symbol:
peek = self.scanner.peek_char()
new_word = str(word+peek)
if new_word in self._symbols:
self.scanner.get_word()
self.current_word = new_word
return self._symbols.get(new_word)
else:
return self._symbols.get(word)
return None
def is_done(self):
return self.scanner.eof
def is_real(self):
if self.current_token != TK_A_DIGIT:
return False
number = self.current_word
if self.scanner.peek_char() == ".":
if not self.get_next_token() == TK_DOT:
raise ValueError("Invalid Digit: '%s'" % str(number)+self.current_word)
self.get_next_token()
if self.current_token != TK_A_DIGIT:
raise ValueError("Invalid Digit: '%s'" % str(number)+self.current_word)
self.current_word = number+'.'+self.current_word
self.current_token = TK_A_REAL
return True
else:
self.current_token = TK_AN_INTEGER
return False
def print_token(self, token=None):
if not token:
token = self.current_token
return token_map.get(token, "Unknown")
