Ben Murdoch | 7757ec2 | 2013-07-23 11:17:36 +0100 | [diff] [blame] | 1 | # Copyright (C) 2013 Google Inc. All rights reserved. |
| 2 | # |
| 3 | # Redistribution and use in source and binary forms, with or without |
| 4 | # modification, are permitted provided that the following conditions are |
| 5 | # met: |
| 6 | # |
| 7 | # * Redistributions of source code must retain the above copyright |
| 8 | # notice, this list of conditions and the following disclaimer. |
| 9 | # * Redistributions in binary form must reproduce the above |
| 10 | # copyright notice, this list of conditions and the following disclaimer |
| 11 | # in the documentation and/or other materials provided with the |
| 12 | # distribution. |
| 13 | # * Neither the name of Google Inc. nor the names of its |
| 14 | # contributors may be used to endorse or promote products derived from |
| 15 | # this software without specific prior written permission. |
| 16 | # |
| 17 | # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 18 | # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 19 | # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 20 | # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 21 | # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 22 | # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 23 | # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 24 | # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 25 | # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 26 | # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 27 | # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 28 | |
| 29 | """Lexer for Blink IDL. |
| 30 | |
| 31 | The lexer uses the PLY (Python Lex-Yacc) library to build a tokenizer which |
| 32 | understands the Blink dialect of Web IDL and produces a token stream suitable |
| 33 | for the Blink IDL parser. |
| 34 | |
| 35 | Blink IDL is identical to Web IDL at the token level, but the base lexer |
| 36 | does not discard comments. We need to override (and not include comments in |
| 37 | the token stream), as otherwise comments must be explicitly included in the |
| 38 | phrase grammar of the parser. |
| 39 | |
| 40 | FIXME: Change base lexer to discard comments, and simply used the base |
| 41 | lexer, eliminating this separate lexer. |
| 42 | |
| 43 | Web IDL: |
| 44 | http://www.w3.org/TR/WebIDL/ |
| 45 | Web IDL Grammar: |
| 46 | http://www.w3.org/TR/WebIDL/#idl-grammar |
| 47 | PLY: |
| 48 | http://www.dabeaz.com/ply/ |
| 49 | """ |
| 50 | |
| 51 | # Disable attribute validation, as lint can't import parent class to check |
| 52 | # pylint: disable=E1101 |
| 53 | |
| 54 | import os.path |
| 55 | import sys |
| 56 | |
| 57 | # Base lexer is in Chromium src/tools/idl_parser |
| 58 | module_path, module_name = os.path.split(__file__) |
| 59 | tools_dir = os.path.join(module_path, os.pardir, os.pardir, os.pardir, os.pardir, os.pardir, 'tools') |
| 60 | sys.path.append(tools_dir) |
| 61 | |
| 62 | from idl_parser.idl_lexer import IDLLexer |
| 63 | |
| 64 | REMOVE_TOKENS = ['COMMENT'] |
| 65 | |
| 66 | |
| 67 | class BlinkIDLLexer(IDLLexer): |
| 68 | # ignore comments |
| 69 | def t_COMMENT(self, t): |
| 70 | r'(/\*(.|\n)*?\*/)|(//.*(\n[ \t]*//.*)*)' |
| 71 | self.AddLines(t.value.count('\n')) |
| 72 | |
| 73 | # Analogs to _AddToken/_AddTokens in base lexer |
| 74 | # Needed to remove COMMENT token, since comments ignored |
| 75 | def _RemoveToken(self, token): |
| 76 | try: |
| 77 | self.tokens.remove(token) |
| 78 | except ValueError: |
| 79 | raise RuntimeError('Token "%s" not present, so cannot be removed ' % token) |
| 80 | |
| 81 | def _RemoveTokens(self, tokens): |
| 82 | for token in tokens: |
| 83 | self._RemoveToken(token) |
| 84 | |
| 85 | def __init__(self): |
| 86 | IDLLexer.__init__(self) |
| 87 | self._RemoveTokens(REMOVE_TOKENS) |
| 88 | |
| 89 | |
| 90 | # If run by itself, attempt to build the lexer |
| 91 | if __name__ == '__main__': |
| 92 | lexer = BlinkIDLLexer() |