122 lines
2.9 KiB
Python
122 lines
2.9 KiB
Python
# cython: language_level=3str
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# cython: auto_pickle=False
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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(object):
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def perform(self, token_stream, text):
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pass # abstract
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def __copy__(self):
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return self # immutable, no need to copy
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def __deepcopy__(self, memo):
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return self # immutable, no need to copy
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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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# self.kwargs is almost always unused => avoid call overhead
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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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