grammar.py revision 13663 
1# Copyright (c) 2006-2011 Nathan Binkert <nate@binkert.org>
2# All rights reserved.
3#
4# Redistribution and use in source and binary forms, with or without
5# modification, are permitted provided that the following conditions are
6# met: redistributions of source code must retain the above copyright
7# notice, this list of conditions and the following disclaimer;
8# redistributions in binary form must reproduce the above copyright
9# notice, this list of conditions and the following disclaimer in the
10# documentation and/or other materials provided with the distribution;
11# neither the name of the copyright holders nor the names of its
12# contributors may be used to endorse or promote products derived from
13# this software without specific prior written permission.
14#
15# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
18# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
19# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
21# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
25# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26
27import os
28
29import ply.lex
30import ply.yacc
31
32class ParseError(Exception):
33    def __init__(self, message, token=None):
34        Exception.__init__(self, message)
35        self.token = token
36
37class Grammar(object):
38    def setupLexerFactory(self, **kwargs):
39        if 'module' in kwargs:
40            raise AttributeError("module is an illegal attribute")
41        self.lex_kwargs = kwargs
42
43    def setupParserFactory(self, **kwargs):
44        if 'module' in kwargs:
45            raise AttributeError("module is an illegal attribute")
46
47        if 'output' in kwargs:
48            dir,tab = os.path.split(output)
49            if not tab.endswith('.py'):
50                raise AttributeError('The output file must end with .py')
51            kwargs['outputdir'] = dir
52            kwargs['tabmodule'] = tab[:-3]
53
54        self.yacc_kwargs = kwargs
55
56    def __getattr__(self, attr):
57        if attr == 'lexers':
58            self.lexers = []
59            return self.lexers
60
61        if attr == 'lex_kwargs':
62            self.setupLexerFactory()
63            return self.lex_kwargs
64
65        if attr == 'yacc_kwargs':
66            self.setupParserFactory()
67            return self.yacc_kwargs
68
69        if attr == 'lex':
70            self.lex = ply.lex.lex(module=self, **self.lex_kwargs)
71            return self.lex
72
73        if attr == 'yacc':
74            self.yacc = ply.yacc.yacc(module=self, **self.yacc_kwargs)
75            return self.yacc
76
77        if attr == 'current_lexer':
78            if not self.lexers:
79                return None
80            return self.lexers[-1][0]
81
82        if attr == 'current_source':
83            if not self.lexers:
84                return '<none>'
85            return self.lexers[-1][1]
86
87        if attr == 'current_line':
88            if not self.lexers:
89                return -1
90            return self.current_lexer.lineno
91
92        raise AttributeError(
93            "'%s' object has no attribute '%s'" % (type(self), attr))
94
95    def parse_string(self, data, source='<string>', debug=None, tracking=0):
96        if not isinstance(data, basestring):
97            raise AttributeError(
98                "argument must be a string, was '%s'" % type(f))
99
100        import new
101        lexer = self.lex.clone()
102        lexer.input(data)
103        self.lexers.append((lexer, source))
104        dict = {
105            'productions' : self.yacc.productions,
106            'action'      : self.yacc.action,
107            'goto'        : self.yacc.goto,
108            'errorfunc'   : self.yacc.errorfunc,
109            }
110        parser = new.instance(ply.yacc.LRParser, dict)
111        result = parser.parse(lexer=lexer, debug=debug, tracking=tracking)
112        self.lexers.pop()
113        return result
114
115    def parse_file(self, f, **kwargs):
116        if isinstance(f, basestring):
117            source = f
118            f = file(f, 'r')
119        elif isinstance(f, file):
120            source = f.name
121        else:
122            raise AttributeError(
123                "argument must be either a string or file, was '%s'" % type(f))
124
125        return self.parse_string(f.read(), source, **kwargs)
126
127    def p_error(self, t):
128        if t:
129            msg = "Syntax error at %s:%d:%d\n>>%s<<" % \
130                  (self.current_source, t.lineno, t.lexpos + 1, t.value)
131        else:
132            msg = "Syntax error at end of %s" % (self.current_source, )
133        raise ParseError(msg, t)
134
135    def t_error(self, t):
136        msg = "Illegal character %s @ %d:%d" % \
137            (`t.value[0]`, t.lineno, t.lexpos)
138        raise ParseError(msg, t)
139