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""" |
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Python Lexical Analyser |
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Actions for use in token specifications |
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""" |
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class Action: |
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def perform(self, token_stream, text): |
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pass |
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def __copy__(self): |
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return self |
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def __deepcopy__(self, memo): |
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return self |
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class Return(Action): |
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""" |
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Internal Plex action which causes |value| to |
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be returned as the value of the associated token |
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""" |
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def __init__(self, value): |
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self.value = value |
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def perform(self, token_stream, text): |
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return self.value |
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def __repr__(self): |
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return "Return(%r)" % self.value |
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class Call(Action): |
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""" |
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Internal Plex action which causes a function to be called. |
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""" |
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def __init__(self, function): |
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self.function = function |
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def perform(self, token_stream, text): |
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return self.function(token_stream, text) |
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def __repr__(self): |
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return "Call(%s)" % self.function.__name__ |
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class Method(Action): |
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""" |
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Plex action that calls a specific method on the token stream, |
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passing the matched text and any provided constant keyword arguments. |
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""" |
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def __init__(self, name, **kwargs): |
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self.name = name |
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self.kwargs = kwargs or None |
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def perform(self, token_stream, text): |
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method = getattr(token_stream, self.name) |
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return method(text, **self.kwargs) if self.kwargs is not None else method(text) |
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def __repr__(self): |
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kwargs = ( |
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', '.join(sorted(['%s=%r' % item for item in self.kwargs.items()])) |
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if self.kwargs is not None else '') |
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return "Method(%s%s%s)" % (self.name, ', ' if kwargs else '', kwargs) |
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class Begin(Action): |
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""" |
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Begin(state_name) is a Plex action which causes the Scanner to |
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enter the state |state_name|. See the docstring of Plex.Lexicon |
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for more information. |
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""" |
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def __init__(self, state_name): |
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self.state_name = state_name |
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def perform(self, token_stream, text): |
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token_stream.begin(self.state_name) |
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def __repr__(self): |
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return "Begin(%s)" % self.state_name |
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class Ignore(Action): |
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""" |
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IGNORE is a Plex action which causes its associated token |
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to be ignored. See the docstring of Plex.Lexicon for more |
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information. |
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""" |
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def perform(self, token_stream, text): |
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return None |
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def __repr__(self): |
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return "IGNORE" |
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IGNORE = Ignore() |
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class Text(Action): |
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""" |
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TEXT is a Plex action which causes the text of a token to |
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be returned as the value of the token. See the docstring of |
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Plex.Lexicon for more information. |
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""" |
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def perform(self, token_stream, text): |
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return text |
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def __repr__(self): |
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return "TEXT" |
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TEXT = Text() |
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