ext/ply/example/hedit/hedit.py

   1 # -----------------------------------------------------------------------------
   2 # hedit.py
   3 #
   4 # Paring of Fortran H Edit descriptions (Contributed by Pearu Peterson)
   5 #
   6 # These tokens can't be easily tokenized because they are of the following
   7 # form:
   8 #
   9 #   nHc1...cn
  10 #
  11 # where n is a positive integer and c1 ... cn are characters.
  12 #
  13 # This example shows how to modify the state of the lexer to parse
  14 # such tokens
  15 # -----------------------------------------------------------------------------
  16
  17 tokens = (
  18     'H_EDIT_DESCRIPTOR',
  19     )
  20
  21 # Tokens
  22 t_ignore = " \t\n"
  23
  24 def t_H_EDIT_DESCRIPTOR(t):
  25     r"\d+H.*"                     # This grabs all of the remaining text
  26     i = t.value.index('H')
  27     n = eval(t.value[:i])
  28
  29     # Adjust the tokenizing position
  30     t.lexer.lexpos -= len(t.value) - (i+1+n)
  31
  32     t.value = t.value[i+1:i+1+n]
  33     return t
  34
  35 def t_error(t):
  36     print "Illegal character '%s'" % t.value[0]
  37     t.skip(1)
  38
  39 # Build the lexer
  40 import lex
  41 lex.lex()
  42 lex.runmain()
  43
  44