1#!/usr/local/bin/python 2# yply.py 3# 4# Author: David Beazley (dave@dabeaz.com) 5# Date : October 2, 2006 6# 7# Converts a UNIX-yacc specification file into a PLY-compatible 8# specification. To use, simply do this: 9# 10# % python yply.py [-nocode] inputfile.y >myparser.py 11# 12# The output of this program is Python code. In the output, 13# any C code in the original file is included, but is commented. 14# If you use the -nocode option, then all of the C code in the 15# original file is discarded. 16# 17# Disclaimer: This just an example I threw together in an afternoon. 18# It might have some bugs. However, it worked when I tried it on 19# a yacc-specified C++ parser containing 442 rules and 855 parsing 20# states. 21# 22 23import sys 24sys.path.insert(0, "../..") 25 26import ylex 27import yparse 28 29from ply import * 30 31if len(sys.argv) == 1: 32 print("usage : yply.py [-nocode] inputfile") 33 raise SystemExit 34 35if len(sys.argv) == 3: 36 if sys.argv[1] == '-nocode': 37 yparse.emit_code = 0 38 else: 39 print("Unknown option '%s'" % sys.argv[1]) 40 raise SystemExit 41 filename = sys.argv[2] 42else: 43 filename = sys.argv[1] 44 45yacc.parse(open(filename).read()) 46 47print(""" 48if __name__ == '__main__': 49 from ply import * 50 yacc.yacc() 51""") 52