最適化モード

everyday parser PLY

「lex.lex(optimize=1)」「yacc.yacc(optimize=1)」

#!/usr/bin/env python

import ply.lex as lex

tokens = (
  'A',
  'B',
  'C',
)

t_A = r'A'
t_B = r'B'
t_C = r'C'
t_ignore = " \t"

def t_error(t):
    print "Illegal character '%s'" % t.value[0]
    t.lexer.skip(1)

lex.lex(optimize=1)


import ply.yacc as yacc

def p_input(p):
    'input : A B C'

def p_error(p):
    print "Syntax error at '%s'" % p.value

yacc.yacc(optimize=1)

while 1:
    try:
        s = raw_input('input > ')
    except EOFError:
        break
    if not s: continue
    yacc.parse(s)

で、

input > A B C
Illegal character 'A'
Illegal character ' '
Illegal character 'B'
Illegal character ' '
Illegal character 'C'
yacc: Parse error in input. EOF

謎