| # Copyright 2018 The Chromium OS Authors. All rights reserved. |
| # Use of this source code is governed by a BSD-style license that can be |
| # found in the LICENSE file. |
| |
| """Module to represent tokens as a stream.""" |
| |
| import logging |
| |
| |
| class TokenStream(object): |
| """Class representing a stream of tokens. |
| |
| Used by the symbol.BaseSymbol classes, which consume tokens from this |
| stream when created. |
| """ |
| |
| def __init__(self, token_list): |
| self._tokens = token_list |
| self._index = 0 |
| |
| def current_token(self): |
| if not self.is_empty(): |
| logging.debug('current_token called: "%s"', |
| self._tokens[self._index]) |
| return self._tokens[self._index] |
| return None |
| |
| def advance_token(self): |
| self._index += 1 |
| |
| def is_empty(self): |
| return len(self._tokens) <= self._index |
