ply: add a base class called Grammar that encapsulates a ply grammar

1 files changed, 119 insertions, 0 deletions

diff --git a/src/python/m5/util/grammar.py b/src/python/m5/util/grammar.py
new file mode 100644
index 000000000..93c2c84c4
--- /dev/null
+++ b/src/python/m5/util/grammar.py
@@ -0,0 +1,119 @@
+# Copyright (c) 2006-2009 Nathan Binkert <nate@binkert.org>
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met: redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer;
+# redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution;
+# neither the name of the copyright holders nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+from ply import lex, yacc
+
+class TokenError(lex.LexError):
+    def __init__(self, msg, t):
+        super(TokenError, self).__init__(msg)
+        self.token = t
+
+class ParseError(yacc.YaccError):
+    def __init__(self, message, token=None):
+        super(ParseError, self).__init__(message)
+        self.token = token
+
+class Tokenizer(object):
+    def __init__(self, lexer, data):
+        if isinstance(data, basestring):
+            indata = [ data ]
+        elif isinstance(data, file):
+            indata = data.xreadlines()
+        else:
+            indata = data
+
+        def _input():
+            for i,line in enumerate(indata):
+                lexer.lineno = i + 1
+                lexer.input(line)
+                while True:
+                    tok = lexer.token()
+                    if not tok:
+                        break
+                    yield tok
+        self.input = _input()
+
+    def next(self):
+        return self.input.next()
+
+    def __iter__(self):
+        return self
+
+    def token(self):
+        try:
+            return self.next()
+        except StopIteration:
+            return None
+
+class Grammar(object):
+    def __init__(self, output=None, debug=False):
+        self.yacc_args = {}
+        self.yacc_args['debug'] = debug
+
+        if output:
+            import os
+
+            dir,tab = os.path.split(output)
+            if not tab.endswith('.py'):
+                raise AttributeError, 'The output file must end with .py'
+            self.yacc_args['outputdir'] = dir
+            self.yacc_args['tabmodule'] = tab[:-3]
+
+    def t_error(self, t):
+        raise lex.LexError("Illegal character %s @ %d:%d" % \
+              (`t.value[0]`, t.lineno, t.lexpos), `t.value[0]`)
+
+    def p_error(self, t):
+        if t:
+            msg = "Syntax error at %d:%d\n>>%s<<" % \
+                  (t.lineno, t.lexpos + 1, t.value)
+        else:
+            msg = "Syntax error at end of input"
+        raise ParseError(msg, t)
+
+    def __getattr__(self, attr):
+        if attr == 'parser':
+            import ply.yacc
+            parser = ply.yacc.yacc(module=self, **self.yacc_args)
+            self.parser = parser
+            return parser
+
+        if attr == 'lexer':
+            import ply.lex
+            lexer = ply.lex.lex(module=self)
+            self.lexer = lexer
+            return lexer
+
+        raise AttributeError, "'%s' object has no attribute '%s'" % \
+              (self.__class__.__name__, attr)
+
+    def parse(self, stmt, **kwargs):
+        self.lexer.lineno = 1
+        result = self.parser.parse(lexer=Tokenizer(self.lexer, stmt), **kwargs)
+        self.parser.restart()
+
+        return result
+