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#=======================================================================
#
# 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__
|
