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Editing: driver.py
# 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 io import os import logging import pkgutil 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 = "" 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.""" with io.open(filename, "r", encoding=encoding) as stream: return self.parse_stream(stream, debug) def parse_string(self, text, debug=False): """Parse a string and return the syntax tree.""" tokens = tokenize.generate_tokens(io.StringIO(text).readline) return self.parse_tokens(tokens, debug) def _generate_pickle_name(gt): head, tail = os.path.splitext(gt) if tail == ".txt": tail = "" return head + tail + ".".join(map(str, sys.version_info)) + ".pickle" 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() gp = _generate_pickle_name(gt) if gp is None else gp 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 OSError as e: logger.info("Writing failed: %s", 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) def load_packaged_grammar(package, grammar_source): """Normally, loads a pickled grammar by doing pkgutil.get_data(package, pickled_grammar) where *pickled_grammar* is computed from *grammar_source* by adding the Python version and using a ``.pickle`` extension. However, if *grammar_source* is an extant file, load_grammar(grammar_source) is called instead. This facilitates using a packaged grammar file when needed but preserves load_grammar's automatic regeneration behavior when possible. """ if os.path.isfile(grammar_source): return load_grammar(grammar_source) pickled_name = _generate_pickle_name(os.path.basename(grammar_source)) data = pkgutil.get_data(package, pickled_name) g = grammar.Grammar() g.loads(data) return g def main(*args): """Main program, when run as a script: produce grammar pickle files. Calls load_grammar for each argument, a path to a grammar text file. """ if not args: args = sys.argv[1:] logging.basicConfig(level=logging.INFO, stream=sys.stdout, format='%(message)s') for gt in args: load_grammar(gt, save=True, force=True) return True if __name__ == "__main__": sys.exit(int(not main()))
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