symbian-qemu-0.9.1-12/python-win32-2.6.1/lib/json/scanner.py
author Mike Kinghan <mikek@symbian.org>
Thu, 25 Nov 2010 14:08:02 +0000
branchGCC_SURGE
changeset 133 bdd30170987b
parent 1 2fb8b9db1c86
permissions -rw-r--r--
Provide an option for the base/rom extension that causes the toolchain id (ARMCC or GCCE) to be defined for the C preprocessor phase of rombuild, enabling rom files to be conditionally included or excluded depending on whether the toolchain can build them. This mimics the same change for Beagleboard.

"""Iterator based sre token scanner

"""

import re
import sre_parse
import sre_compile
import sre_constants

from re import VERBOSE, MULTILINE, DOTALL
from sre_constants import BRANCH, SUBPATTERN

__all__ = ['Scanner', 'pattern']

FLAGS = (VERBOSE | MULTILINE | DOTALL)

class Scanner(object):
    def __init__(self, lexicon, flags=FLAGS):
        self.actions = [None]
        # Combine phrases into a compound pattern
        s = sre_parse.Pattern()
        s.flags = flags
        p = []
        for idx, token in enumerate(lexicon):
            phrase = token.pattern
            try:
                subpattern = sre_parse.SubPattern(s,
                    [(SUBPATTERN, (idx + 1, sre_parse.parse(phrase, flags)))])
            except sre_constants.error:
                raise
            p.append(subpattern)
            self.actions.append(token)

        s.groups = len(p) + 1 # NOTE(guido): Added to make SRE validation work
        p = sre_parse.SubPattern(s, [(BRANCH, (None, p))])
        self.scanner = sre_compile.compile(p)

    def iterscan(self, string, idx=0, context=None):
        """Yield match, end_idx for each match

        """
        match = self.scanner.scanner(string, idx).match
        actions = self.actions
        lastend = idx
        end = len(string)
        while True:
            m = match()
            if m is None:
                break
            matchbegin, matchend = m.span()
            if lastend == matchend:
                break
            action = actions[m.lastindex]
            if action is not None:
                rval, next_pos = action(m, context)
                if next_pos is not None and next_pos != matchend:
                    # "fast forward" the scanner
                    matchend = next_pos
                    match = self.scanner.scanner(string, matchend).match
                yield rval, matchend
            lastend = matchend


def pattern(pattern, flags=FLAGS):
    def decorator(fn):
        fn.pattern = pattern
        fn.regex = re.compile(pattern, flags)
        return fn
    return decorator