Error in Plex

srijit at srijit at
Wed Jan 19 00:54:00 EST 2005

I got the following error while using Plex

Traceback (most recent call last):
  File "", line 1, in ?
    from Plex import *
  File "D:\python24\lib\site-packages\Plex\", line 34, in ?
    from Lexicons import Lexicon, State
  File "D:\python24\lib\site-packages\Plex\", line 12, in ?
    import DFA
  File "D:\python24\lib\site-packages\Plex\", line 9, in ?
    import Machines
  File "D:\python24\lib\site-packages\Plex\", line 14, in ?
    from Transitions import TransitionMap
  File "D:\python24\lib\site-packages\Plex\", line 85
    def get_epsilon(self,
SyntaxError: Invalid syntax.  Assignment to None.

The corresponding source code :


from Plex import *

lexicon = Lexicon([
    (Str("Python"),      "my_favourite_language"),
    (Str("Perl"),        "the_other_language"),
    (Str("rocks"),       "is_excellent"),
    (Str("sucks"),       "is_differently_good"),
    (Rep1(Any(" \t\n")), IGNORE)

filename = "plex1.txt"
f = open(filename, "r")
scanner = Scanner(lexicon, f, filename)
while 1:
    token =
    print token
    if token[0] is None:

The error was removed when I used the following code in

def get_epsilon(self,
    none = None):
    Return the mapping for epsilon, or None.
    return self.special.get('', None)


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