| # Copyright 2004-2005 Elemental Security, Inc. All Rights Reserved. | |
| # Licensed to PSF under a Contributor Agreement. | |
| # Modifications: | |
| # Copyright 2006 Google, Inc. All Rights Reserved. | |
| # Licensed to PSF under a Contributor Agreement. | |
| """Parser driver. | |
| This provides a high-level interface to parse a file into a syntax tree. | |
| """ | |
| __author__ = "Guido van Rossum <guido@python.org>" | |
| __all__ = ["Driver", "load_grammar"] | |
| # Python imports | |
| import codecs | |
| import os | |
| import logging | |
| import StringIO | |
| import sys | |
| # Pgen imports | |
| from . import grammar, parse, token, tokenize, pgen | |
| class Driver(object): | |
| def __init__(self, grammar, convert=None, logger=None): | |
| self.grammar = grammar | |
| if logger is None: | |
| logger = logging.getLogger() | |
| self.logger = logger | |
| self.convert = convert | |
| def parse_tokens(self, tokens, debug=False): | |
| """Parse a series of tokens and return the syntax tree.""" | |
| # XXX Move the prefix computation into a wrapper around tokenize. | |
| p = parse.Parser(self.grammar, self.convert) | |
| p.setup() | |
| lineno = 1 | |
| column = 0 | |
| type = value = start = end = line_text = None | |
| prefix = u"" | |
| for quintuple in tokens: | |
| type, value, start, end, line_text = quintuple | |
| if start != (lineno, column): | |
| assert (lineno, column) <= start, ((lineno, column), start) | |
| s_lineno, s_column = start | |
| if lineno < s_lineno: | |
| prefix += "\n" * (s_lineno - lineno) | |
| lineno = s_lineno | |
| column = 0 | |
| if column < s_column: | |
| prefix += line_text[column:s_column] | |
| column = s_column | |
| if type in (tokenize.COMMENT, tokenize.NL): | |
| prefix += value | |
| lineno, column = end | |
| if value.endswith("\n"): | |
| lineno += 1 | |
| column = 0 | |
| continue | |
| if type == token.OP: | |
| type = grammar.opmap[value] | |
| if debug: | |
| self.logger.debug("%s %r (prefix=%r)", | |
| token.tok_name[type], value, prefix) | |
| if p.addtoken(type, value, (prefix, start)): | |
| if debug: | |
| self.logger.debug("Stop.") | |
| break | |
| prefix = "" | |
| lineno, column = end | |
| if value.endswith("\n"): | |
| lineno += 1 | |
| column = 0 | |
| else: | |
| # We never broke out -- EOF is too soon (how can this happen???) | |
| raise parse.ParseError("incomplete input", | |
| type, value, (prefix, start)) | |
| return p.rootnode | |
| def parse_stream_raw(self, stream, debug=False): | |
| """Parse a stream and return the syntax tree.""" | |
| tokens = tokenize.generate_tokens(stream.readline) | |
| return self.parse_tokens(tokens, debug) | |
| def parse_stream(self, stream, debug=False): | |
| """Parse a stream and return the syntax tree.""" | |
| return self.parse_stream_raw(stream, debug) | |
| def parse_file(self, filename, encoding=None, debug=False): | |
| """Parse a file and return the syntax tree.""" | |
| stream = codecs.open(filename, "r", encoding) | |
| try: | |
| return self.parse_stream(stream, debug) | |
| finally: | |
| stream.close() | |
| def parse_string(self, text, debug=False): | |
| """Parse a string and return the syntax tree.""" | |
| tokens = tokenize.generate_tokens(StringIO.StringIO(text).readline) | |
| return self.parse_tokens(tokens, debug) | |
| def load_grammar(gt="Grammar.txt", gp=None, | |
| save=True, force=False, logger=None): | |
| """Load the grammar (maybe from a pickle).""" | |
| if logger is None: | |
| logger = logging.getLogger() | |
| if gp is None: | |
| head, tail = os.path.splitext(gt) | |
| if tail == ".txt": | |
| tail = "" | |
| gp = head + tail + ".".join(map(str, sys.version_info)) + ".pickle" | |
| if force or not _newer(gp, gt): | |
| logger.info("Generating grammar tables from %s", gt) | |
| g = pgen.generate_grammar(gt) | |
| if save: | |
| logger.info("Writing grammar tables to %s", gp) | |
| try: | |
| g.dump(gp) | |
| except IOError, e: | |
| logger.info("Writing failed:"+str(e)) | |
| else: | |
| g = grammar.Grammar() | |
| g.load(gp) | |
| return g | |
| def _newer(a, b): | |
| """Inquire whether file a was written since file b.""" | |
| if not os.path.exists(a): | |
| return False | |
| if not os.path.exists(b): | |
| return True | |
| return os.path.getmtime(a) >= os.path.getmtime(b) |