"""

 Name: 

 Author: Eugen Sawin <sawine@informatik.uni-freiburg.de>

 """

 from os import path

 import os

 import re

 import token

 NOT = "~"

 AND = "&"

 OR = "|"

 IMP = "->"

 EQ = "<->"

 BOX = "[]"

 DIAMOND = "<>"

 P = "p"

 TOKENS = {re.compile("~"): NOT,

           re.compile("&"): AND,

           re.compile("\|"): OR,

           re.compile("->"): IMP,

           re.compile("<->"): EQ,

           re.compile("\[\]"): BOX,

           re.compile("<>"): DIAMOND,

           re.compile("[a-z]+"): P}

 class Scanner(object):

     def __init__(self, tokens, source=None):

         self.tokens = tokens

         self.reset(source)

     def next(self):         

         while self.i < len(self.source):           

             for p, token in self.tokens.iteritems():

                 m = p.match(self.source[self.i:])               

                 if m:                  

                     self.i += m.end(0)

                     value = m.group(0)

                     return (token, value)

             self.i += 1

     def reset(self, source):

         self.i = 0

         self.source = source

 class Parser(object):

     def __init__(self, scanner):

         self.scanner = scanner

     def parse(self, source):

         self.scanner.reset(source)

         token = self.scanner.next()

         while token:

             print token

             token = self.scanner.next()

 def main():

     args = parse_arguments()

     scanner = Scanner(TOKENS)

     parser = Parser(scanner)

     parser.parse(args.formula)

 from argparse import ArgumentParser

 def parse_arguments():

     parser = ArgumentParser(description="Parses Simple Modal Logic syntax.")

     parser.add_argument("formula", help="your formula") 

     return parser.parse_args()

 if __name__ == "__main__":

     main()