Merged revisions 61596-61597 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/trunk

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  r61596 | martin.v.loewis | 2008-03-18 23:43:46 -0500 (Di, 18 Mär 2008) | 2 lines

  Import lib2to3.
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  r61597 | martin.v.loewis | 2008-03-18 23:58:04 -0500 (Di, 18 Mär 2008) | 3 lines

  Initialized merge tracking via "svnmerge" with revisions "1-61595" from
  svn+ssh://pythondev@svn.python.org/sandbox/trunk/2to3/lib2to3
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1 files changed, 143 insertions, 0 deletions

diff --git a/Lib/lib2to3/pgen2/driver.py b/Lib/lib2to3/pgen2/driver.py
new file mode 100644
index 0000000..77e2a40
--- /dev/null
+++ b/Lib/lib2to3/pgen2/driver.py
@@ -0,0 +1,143 @@
+# 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 os
+import logging
+import sys
+
+# Pgen imports
+from . import grammar, parse, token, tokenize
+
+
+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", t, v, x)
+        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, debug=False):
+        """Parse a file and return the syntax tree."""
+        stream = open(filename)
+        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(generate_lines(text).next)
+        return self.parse_tokens(tokens, debug)
+
+
+def generate_lines(text):
+    """Generator that behaves like readline without using StringIO."""
+    for line in text.splitlines(True):
+        yield line
+    while True:
+        yield ""
+
+
+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)
+        from pgen2 import pgen
+        g = pgen.generate_grammar(gt)
+        if save:
+            logger.info("Writing grammar tables to %s", gp)
+            g.dump(gp)
+    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)