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#-----------------------------------------------------------------
# plyparser.py
#
# PLYParser class and other utilites for simplifying programming
# parsers with PLY
#
# Copyright (C) 2008-2015, Eli Bendersky
# License: BSD
#-----------------------------------------------------------------
class Coord(object):
""" Coordinates of a syntactic element. Consists of:
- File name
- Line number
- (optional) column number, for the Lexer
"""
__slots__ = ('file', 'line', 'column', '__weakref__')
def __init__(self, file, line, column=None):
self.file = file
self.line = line
self.column = column
def __str__(self):
str = "%s:%s" % (self.file, self.line)
if self.column: str += ":%s" % self.column
return str
class ParseError(Exception): pass
class PLYParser(object):
def _create_opt_rule(self, rulename):
""" Given a rule name, creates an optional ply.yacc rule
for it. The name of the optional rule is
<rulename>_opt
"""
optname = rulename + '_opt'
def optrule(self, p):
p[0] = p[1]
optrule.__doc__ = '%s : empty\n| %s' % (optname, rulename)
optrule.__name__ = 'p_%s' % optname
setattr(self.__class__, optrule.__name__, optrule)
def _coord(self, lineno, column=None):
return Coord(
file=self.clex.filename,
line=lineno,
column=column)
def _parse_error(self, msg, coord):
raise ParseError("%s: %s" % (coord, msg))
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