#!/usr/bin/env python

# python_201_plex1.py
#
# Sample Plex lexer
#

import sys
import Plex

def test(infileName):
    letter = Plex.Range("AZaz")
    digit =  Plex.Range("09")
    name = letter +  Plex.Rep(letter | digit)
    number =  Plex.Rep1(digit)
    space =  Plex.Any(" \t\n")
    comment =  Plex.Str('"') +  Plex.Rep( Plex.AnyBut('"')) +  Plex.Str('"')
    resword =  Plex.Str("if", "then", "else", "end")
    lexicon =  Plex.Lexicon([
        (resword,         'keyword'),
        (name,            'ident'),
        (number,          'int'),
        ( Plex.Any("+-*/=<>"),   Plex.TEXT),
        (space,  Plex.IGNORE),
        (comment, 'comment'),
    ])
    infile = open(infileName, "r")
    scanner =  Plex.Scanner(lexicon, infile, infileName)
    while 1:
        token = scanner.read()
        position = scanner.position()
        print '(%d, %d) tok: %s  tokType: %s' % \
            (position[1], position[2], token[1], token[0])
        if token[0] is None:
            break

USAGE_TEXT = """
Usage: python python_201_plex1.py <infile>
"""

def usage():
    print USAGE_TEXT
    sys.exit(-1)

def main():
    args = sys.argv[1:]
    if len(args) != 1:
        usage()
    infileName = args[0]
    test(infileName)

if __name__ == '__main__':
    main()
    #import pdb
    #pdb.run('main()')