| #======================================================================= |
| # |
| # Python Lexical Analyser |
| # |
| # Actions for use in token specifications |
| # |
| #======================================================================= |
| |
| class Action(object): |
| |
| def perform(self, token_stream, text): |
| pass # abstract |
| |
| def same_as(self, other): |
| return self is other |
| |
| |
| class Return(Action): |
| """ |
| Internal Plex action which causes |value| to |
| be returned as the value of the associated token |
| """ |
| |
| def __init__(self, value): |
| self.value = value |
| |
| def perform(self, token_stream, text): |
| return self.value |
| |
| def same_as(self, other): |
| return isinstance(other, Return) and self.value == other.value |
| |
| def __repr__(self): |
| return "Return(%s)" % repr(self.value) |
| |
| |
| class Call(Action): |
| """ |
| Internal Plex action which causes a function to be called. |
| """ |
| |
| def __init__(self, function): |
| self.function = function |
| |
| def perform(self, token_stream, text): |
| return self.function(token_stream, text) |
| |
| def __repr__(self): |
| return "Call(%s)" % self.function.__name__ |
| |
| def same_as(self, other): |
| return isinstance(other, Call) and self.function is other.function |
| |
| |
| class Begin(Action): |
| """ |
| Begin(state_name) is a Plex action which causes the Scanner to |
| enter the state |state_name|. See the docstring of Plex.Lexicon |
| for more information. |
| """ |
| |
| def __init__(self, state_name): |
| self.state_name = state_name |
| |
| def perform(self, token_stream, text): |
| token_stream.begin(self.state_name) |
| |
| def __repr__(self): |
| return "Begin(%s)" % self.state_name |
| |
| def same_as(self, other): |
| return isinstance(other, Begin) and self.state_name == other.state_name |
| |
| |
| class Ignore(Action): |
| """ |
| IGNORE is a Plex action which causes its associated token |
| to be ignored. See the docstring of Plex.Lexicon for more |
| information. |
| """ |
| def perform(self, token_stream, text): |
| return None |
| |
| def __repr__(self): |
| return "IGNORE" |
| |
| IGNORE = Ignore() |
| #IGNORE.__doc__ = Ignore.__doc__ |
| |
| class Text(Action): |
| """ |
| TEXT is a Plex action which causes the text of a token to |
| be returned as the value of the token. See the docstring of |
| Plex.Lexicon for more information. |
| """ |
| |
| def perform(self, token_stream, text): |
| return text |
| |
| def __repr__(self): |
| return "TEXT" |
| |
| TEXT = Text() |
| #TEXT.__doc__ = Text.__doc__ |
| |
| |