third_party/cython/src/Cython/Plex/Actions.py

   1 #=======================================================================
   2 #
   3 #   Python Lexical Analyser
   4 #
   5 #   Actions for use in token specifications
   6 #
   7 #=======================================================================
   8
   9 class Action(object):
  10
  11   def perform(self, token_stream, text):
  12     pass # abstract
  13
  14   def same_as(self, other):
  15     return self is other
  16
  17
  18 class Return(Action):
  19   """
  20   Internal Plex action which causes |value| to
  21   be returned as the value of the associated token
  22   """
  23
  24   def __init__(self, value):
  25     self.value = value
  26
  27   def perform(self, token_stream, text):
  28     return self.value
  29
  30   def same_as(self, other):
  31     return isinstance(other, Return) and self.value == other.value
  32
  33   def __repr__(self):
  34     return "Return(%s)" % repr(self.value)
  35
  36
  37 class Call(Action):
  38   """
  39   Internal Plex action which causes a function to be called.
  40   """
  41
  42   def __init__(self, function):
  43     self.function = function
  44
  45   def perform(self, token_stream, text):
  46     return self.function(token_stream, text)
  47
  48   def __repr__(self):
  49     return "Call(%s)" % self.function.__name__
  50
  51   def same_as(self, other):
  52     return isinstance(other, Call) and self.function is other.function
  53
  54
  55 class Begin(Action):
  56   """
  57   Begin(state_name) is a Plex action which causes the Scanner to
  58   enter the state |state_name|. See the docstring of Plex.Lexicon
  59   for more information.
  60   """
  61
  62   def __init__(self, state_name):
  63     self.state_name = state_name
  64
  65   def perform(self, token_stream, text):
  66     token_stream.begin(self.state_name)
  67
  68   def __repr__(self):
  69     return "Begin(%s)" % self.state_name
  70
  71   def same_as(self, other):
  72     return isinstance(other, Begin) and self.state_name == other.state_name
  73
  74
  75 class Ignore(Action):
  76   """
  77   IGNORE is a Plex action which causes its associated token
  78   to be ignored. See the docstring of Plex.Lexicon  for more
  79   information.
  80   """
  81   def perform(self, token_stream, text):
  82     return None
  83
  84   def __repr__(self):
  85     return "IGNORE"
  86
  87 IGNORE = Ignore()
  88 #IGNORE.__doc__ = Ignore.__doc__
  89
  90 class Text(Action):
  91   """
  92   TEXT is a Plex action which causes the text of a token to
  93   be returned as the value of the token. See the docstring of
  94   Plex.Lexicon  for more information.
  95   """
  96
  97   def perform(self, token_stream, text):
  98     return text
  99
 100   def __repr__(self):
 101     return "TEXT"
 102
 103 TEXT = Text()
 104 #TEXT.__doc__ = Text.__doc__
 105
 106