553 lines
20 KiB
Python
553 lines
20 KiB
Python
"""Tokenization help for Python programs.
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tokenize(readline) is a generator that breaks a stream of bytes into
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Python tokens. It decodes the bytes according to PEP-0263 for
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determining source file encoding.
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It accepts a readline-like method which is called repeatedly to get the
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next line of input (or b"" for EOF). It generates 5-tuples with these
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members:
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the token type (see token.py)
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the token (a string)
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the starting (row, column) indices of the token (a 2-tuple of ints)
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the ending (row, column) indices of the token (a 2-tuple of ints)
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the original line (string)
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It is designed to match the working of the Python tokenizer exactly, except
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that it produces COMMENT tokens for comments and gives type OP for all
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operators. Additionally, all token lists start with an ENCODING token
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which tells you which encoding was used to decode the bytes stream.
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"""
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__author__ = 'Ka-Ping Yee <ping@lfw.org>'
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__credits__ = ('GvR, ESR, Tim Peters, Thomas Wouters, Fred Drake, '
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'Skip Montanaro, Raymond Hettinger, Trent Nelson, '
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'Michael Foord')
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import re
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import sys
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from token import *
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from codecs import lookup, BOM_UTF8
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cookie_re = re.compile("coding[:=]\s*([-\w.]+)")
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import token
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__all__ = [x for x in dir(token) if not x.startswith("_")]
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__all__.extend(["COMMENT", "tokenize", "detect_encoding", "NL", "untokenize",
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"ENCODING", "TokenInfo"])
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del token
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COMMENT = N_TOKENS
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tok_name[COMMENT] = 'COMMENT'
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NL = N_TOKENS + 1
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tok_name[NL] = 'NL'
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ENCODING = N_TOKENS + 2
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tok_name[ENCODING] = 'ENCODING'
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N_TOKENS += 3
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class TokenInfo(tuple):
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'TokenInfo(type, string, start, end, line)'
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__slots__ = ()
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_fields = ('type', 'string', 'start', 'end', 'line')
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def __new__(cls, type, string, start, end, line):
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return tuple.__new__(cls, (type, string, start, end, line))
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@classmethod
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def _make(cls, iterable, new=tuple.__new__, len=len):
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'Make a new TokenInfo object from a sequence or iterable'
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result = new(cls, iterable)
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if len(result) != 5:
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raise TypeError('Expected 5 arguments, got %d' % len(result))
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return result
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def __repr__(self):
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return 'TokenInfo(type=%r, string=%r, start=%r, end=%r, line=%r)' % self
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def _asdict(self):
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'Return a new dict which maps field names to their values'
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return dict(zip(self._fields, self))
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def _replace(self, **kwds):
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'Return a new TokenInfo object replacing specified fields with new values'
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result = self._make(map(kwds.pop, ('type', 'string', 'start', 'end', 'line'), self))
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if kwds:
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raise ValueError('Got unexpected field names: %r' % kwds.keys())
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return result
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def __getnewargs__(self):
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return tuple(self)
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type = property(lambda t: t[0])
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string = property(lambda t: t[1])
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start = property(lambda t: t[2])
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end = property(lambda t: t[3])
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line = property(lambda t: t[4])
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def group(*choices): return '(' + '|'.join(choices) + ')'
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def any(*choices): return group(*choices) + '*'
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def maybe(*choices): return group(*choices) + '?'
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# Note: we use unicode matching for names ("\w") but ascii matching for
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# number literals.
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Whitespace = r'[ \f\t]*'
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Comment = r'#[^\r\n]*'
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Ignore = Whitespace + any(r'\\\r?\n' + Whitespace) + maybe(Comment)
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Name = r'\w+'
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Hexnumber = r'0[xX][0-9a-fA-F]+'
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Binnumber = r'0[bB][01]+'
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Octnumber = r'0[oO][0-7]+'
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Decnumber = r'(?:0+|[1-9][0-9]*)'
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Intnumber = group(Hexnumber, Binnumber, Octnumber, Decnumber)
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Exponent = r'[eE][-+]?[0-9]+'
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Pointfloat = group(r'[0-9]+\.[0-9]*', r'\.[0-9]+') + maybe(Exponent)
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Expfloat = r'[0-9]+' + Exponent
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Floatnumber = group(Pointfloat, Expfloat)
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Imagnumber = group(r'[0-9]+[jJ]', Floatnumber + r'[jJ]')
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Number = group(Imagnumber, Floatnumber, Intnumber)
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# Tail end of ' string.
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Single = r"[^'\\]*(?:\\.[^'\\]*)*'"
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# Tail end of " string.
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Double = r'[^"\\]*(?:\\.[^"\\]*)*"'
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# Tail end of ''' string.
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Single3 = r"[^'\\]*(?:(?:\\.|'(?!''))[^'\\]*)*'''"
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# Tail end of """ string.
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Double3 = r'[^"\\]*(?:(?:\\.|"(?!""))[^"\\]*)*"""'
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Triple = group("[bB]?[rR]?'''", '[bB]?[rR]?"""')
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# Single-line ' or " string.
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String = group(r"[bB]?[rR]?'[^\n'\\]*(?:\\.[^\n'\\]*)*'",
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r'[bB]?[rR]?"[^\n"\\]*(?:\\.[^\n"\\]*)*"')
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# Because of leftmost-then-longest match semantics, be sure to put the
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# longest operators first (e.g., if = came before ==, == would get
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# recognized as two instances of =).
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Operator = group(r"\*\*=?", r">>=?", r"<<=?", r"!=",
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r"//=?", r"->",
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r"[+\-*/%&|^=<>]=?",
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r"~")
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Bracket = '[][(){}]'
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Special = group(r'\r?\n', r'\.\.\.', r'[:;.,@]')
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Funny = group(Operator, Bracket, Special)
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PlainToken = group(Number, Funny, String, Name)
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Token = Ignore + PlainToken
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# First (or only) line of ' or " string.
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ContStr = group(r"[bB]?[rR]?'[^\n'\\]*(?:\\.[^\n'\\]*)*" +
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group("'", r'\\\r?\n'),
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r'[bB]?[rR]?"[^\n"\\]*(?:\\.[^\n"\\]*)*' +
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group('"', r'\\\r?\n'))
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PseudoExtras = group(r'\\\r?\n', Comment, Triple)
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PseudoToken = Whitespace + group(PseudoExtras, Number, Funny, ContStr, Name)
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def _compile(expr):
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return re.compile(expr, re.UNICODE)
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tokenprog, pseudoprog, single3prog, double3prog = map(
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_compile, (Token, PseudoToken, Single3, Double3))
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endprogs = {"'": _compile(Single), '"': _compile(Double),
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"'''": single3prog, '"""': double3prog,
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"r'''": single3prog, 'r"""': double3prog,
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"b'''": single3prog, 'b"""': double3prog,
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"br'''": single3prog, 'br"""': double3prog,
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"R'''": single3prog, 'R"""': double3prog,
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"B'''": single3prog, 'B"""': double3prog,
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"bR'''": single3prog, 'bR"""': double3prog,
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"Br'''": single3prog, 'Br"""': double3prog,
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"BR'''": single3prog, 'BR"""': double3prog,
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'r': None, 'R': None, 'b': None, 'B': None}
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triple_quoted = {}
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for t in ("'''", '"""',
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"r'''", 'r"""', "R'''", 'R"""',
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"b'''", 'b"""', "B'''", 'B"""',
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"br'''", 'br"""', "Br'''", 'Br"""',
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"bR'''", 'bR"""', "BR'''", 'BR"""'):
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triple_quoted[t] = t
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single_quoted = {}
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for t in ("'", '"',
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"r'", 'r"', "R'", 'R"',
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"b'", 'b"', "B'", 'B"',
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"br'", 'br"', "Br'", 'Br"',
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"bR'", 'bR"', "BR'", 'BR"' ):
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single_quoted[t] = t
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del _compile
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tabsize = 8
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class TokenError(Exception): pass
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class StopTokenizing(Exception): pass
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class Untokenizer:
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def __init__(self):
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self.tokens = []
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self.prev_row = 1
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self.prev_col = 0
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self.encoding = None
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def add_whitespace(self, start):
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row, col = start
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assert row <= self.prev_row
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col_offset = col - self.prev_col
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if col_offset:
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self.tokens.append(" " * col_offset)
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def untokenize(self, iterable):
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for t in iterable:
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if len(t) == 2:
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self.compat(t, iterable)
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break
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tok_type, token, start, end, line = t
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if tok_type == ENCODING:
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self.encoding = token
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continue
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self.add_whitespace(start)
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self.tokens.append(token)
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self.prev_row, self.prev_col = end
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if tok_type in (NEWLINE, NL):
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self.prev_row += 1
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self.prev_col = 0
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return "".join(self.tokens)
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def compat(self, token, iterable):
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startline = False
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indents = []
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toks_append = self.tokens.append
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toknum, tokval = token
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if toknum in (NAME, NUMBER):
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tokval += ' '
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if toknum in (NEWLINE, NL):
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startline = True
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prevstring = False
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for tok in iterable:
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toknum, tokval = tok[:2]
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if toknum == ENCODING:
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self.encoding = tokval
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continue
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if toknum in (NAME, NUMBER):
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tokval += ' '
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# Insert a space between two consecutive strings
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if toknum == STRING:
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if prevstring:
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tokval = ' ' + tokval
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prevstring = True
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else:
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prevstring = False
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if toknum == INDENT:
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indents.append(tokval)
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continue
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elif toknum == DEDENT:
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indents.pop()
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continue
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elif toknum in (NEWLINE, NL):
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startline = True
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elif startline and indents:
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toks_append(indents[-1])
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startline = False
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toks_append(tokval)
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def untokenize(iterable):
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"""Transform tokens back into Python source code.
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It returns a bytes object, encoded using the ENCODING
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token, which is the first token sequence output by tokenize.
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Each element returned by the iterable must be a token sequence
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with at least two elements, a token number and token value. If
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only two tokens are passed, the resulting output is poor.
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Round-trip invariant for full input:
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Untokenized source will match input source exactly
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Round-trip invariant for limited intput:
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# Output bytes will tokenize the back to the input
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t1 = [tok[:2] for tok in tokenize(f.readline)]
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newcode = untokenize(t1)
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readline = BytesIO(newcode).readline
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t2 = [tok[:2] for tok in tokenize(readline)]
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assert t1 == t2
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"""
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ut = Untokenizer()
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out = ut.untokenize(iterable)
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if ut.encoding is not None:
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out = out.encode(ut.encoding)
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return out
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def _get_normal_name(orig_enc):
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"""Imitates get_normal_name in tokenizer.c."""
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# Only care about the first 12 characters.
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enc = orig_enc[:12].lower().replace("_", "-")
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if enc == "utf-8" or enc.startswith("utf-8-"):
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return "utf-8"
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if enc in ("latin-1", "iso-8859-1", "iso-latin-1") or \
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enc.startswith(("latin-1-", "iso-8859-1-", "iso-latin-1-")):
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return "iso-8859-1"
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return orig_enc
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def detect_encoding(readline):
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"""
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The detect_encoding() function is used to detect the encoding that should
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be used to decode a Python source file. It requires one argment, readline,
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in the same way as the tokenize() generator.
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It will call readline a maximum of twice, and return the encoding used
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(as a string) and a list of any lines (left as bytes) it has read in.
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It detects the encoding from the presence of a utf-8 bom or an encoding
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cookie as specified in pep-0263. If both a bom and a cookie are present,
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but disagree, a SyntaxError will be raised. If the encoding cookie is an
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invalid charset, raise a SyntaxError. Note that if a utf-8 bom is found,
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'utf-8-sig' is returned.
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If no encoding is specified, then the default of 'utf-8' will be returned.
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"""
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bom_found = False
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encoding = None
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default = 'utf-8'
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def read_or_stop():
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try:
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return readline()
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except StopIteration:
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return b''
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def find_cookie(line):
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try:
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line_string = line.decode('ascii')
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except UnicodeDecodeError:
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return None
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matches = cookie_re.findall(line_string)
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if not matches:
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return None
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encoding = _get_normal_name(matches[0])
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try:
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codec = lookup(encoding)
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except LookupError:
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# This behaviour mimics the Python interpreter
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raise SyntaxError("unknown encoding: " + encoding)
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if bom_found:
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if codec.name != 'utf-8':
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# This behaviour mimics the Python interpreter
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raise SyntaxError('encoding problem: utf-8')
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encoding += '-sig'
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return encoding
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first = read_or_stop()
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if first.startswith(BOM_UTF8):
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bom_found = True
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first = first[3:]
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default = 'utf-8-sig'
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if not first:
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return default, []
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encoding = find_cookie(first)
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if encoding:
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return encoding, [first]
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second = read_or_stop()
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if not second:
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return default, [first]
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encoding = find_cookie(second)
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if encoding:
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return encoding, [first, second]
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return default, [first, second]
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def tokenize(readline):
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"""
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The tokenize() generator requires one argment, readline, which
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must be a callable object which provides the same interface as the
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readline() method of built-in file objects. Each call to the function
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should return one line of input as bytes. Alternately, readline
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can be a callable function terminating with StopIteration:
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readline = open(myfile, 'rb').__next__ # Example of alternate readline
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The generator produces 5-tuples with these members: the token type; the
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token string; a 2-tuple (srow, scol) of ints specifying the row and
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column where the token begins in the source; a 2-tuple (erow, ecol) of
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ints specifying the row and column where the token ends in the source;
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and the line on which the token was found. The line passed is the
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logical line; continuation lines are included.
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The first token sequence will always be an ENCODING token
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which tells you which encoding was used to decode the bytes stream.
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"""
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# This import is here to avoid problems when the itertools module is not
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# built yet and tokenize is imported.
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from itertools import chain, repeat
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encoding, consumed = detect_encoding(readline)
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rl_gen = iter(readline, b"")
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empty = repeat(b"")
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return _tokenize(chain(consumed, rl_gen, empty).__next__, encoding)
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def _tokenize(readline, encoding):
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lnum = parenlev = continued = 0
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numchars = '0123456789'
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contstr, needcont = '', 0
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contline = None
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indents = [0]
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if encoding is not None:
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if encoding == "utf-8-sig":
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# BOM will already have been stripped.
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encoding = "utf-8"
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yield TokenInfo(ENCODING, encoding, (0, 0), (0, 0), '')
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while True: # loop over lines in stream
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try:
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line = readline()
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except StopIteration:
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line = b''
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if encoding is not None:
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line = line.decode(encoding)
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lnum += 1
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pos, max = 0, len(line)
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if contstr: # continued string
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if not line:
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raise TokenError("EOF in multi-line string", strstart)
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endmatch = endprog.match(line)
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if endmatch:
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pos = end = endmatch.end(0)
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yield TokenInfo(STRING, contstr + line[:end],
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strstart, (lnum, end), contline + line)
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contstr, needcont = '', 0
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contline = None
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elif needcont and line[-2:] != '\\\n' and line[-3:] != '\\\r\n':
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yield TokenInfo(ERRORTOKEN, contstr + line,
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strstart, (lnum, len(line)), contline)
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contstr = ''
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contline = None
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continue
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else:
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contstr = contstr + line
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contline = contline + line
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continue
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elif parenlev == 0 and not continued: # new statement
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if not line: break
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column = 0
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while pos < max: # measure leading whitespace
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if line[pos] == ' ':
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column += 1
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elif line[pos] == '\t':
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column = (column//tabsize + 1)*tabsize
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elif line[pos] == '\f':
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column = 0
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else:
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break
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pos += 1
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if pos == max:
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break
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if line[pos] in '#\r\n': # skip comments or blank lines
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if line[pos] == '#':
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comment_token = line[pos:].rstrip('\r\n')
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nl_pos = pos + len(comment_token)
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yield TokenInfo(COMMENT, comment_token,
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(lnum, pos), (lnum, pos + len(comment_token)), line)
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yield TokenInfo(NL, line[nl_pos:],
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(lnum, nl_pos), (lnum, len(line)), line)
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else:
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yield TokenInfo((NL, COMMENT)[line[pos] == '#'], line[pos:],
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(lnum, pos), (lnum, len(line)), line)
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continue
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if column > indents[-1]: # count indents or dedents
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indents.append(column)
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yield TokenInfo(INDENT, line[:pos], (lnum, 0), (lnum, pos), line)
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while column < indents[-1]:
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if column not in indents:
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raise IndentationError(
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"unindent does not match any outer indentation level",
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("<tokenize>", lnum, pos, line))
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indents = indents[:-1]
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yield TokenInfo(DEDENT, '', (lnum, pos), (lnum, pos), line)
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else: # continued statement
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if not line:
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raise TokenError("EOF in multi-line statement", (lnum, 0))
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continued = 0
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while pos < max:
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pseudomatch = pseudoprog.match(line, pos)
|
|
if pseudomatch: # scan for tokens
|
|
start, end = pseudomatch.span(1)
|
|
spos, epos, pos = (lnum, start), (lnum, end), end
|
|
token, initial = line[start:end], line[start]
|
|
|
|
if (initial in numchars or # ordinary number
|
|
(initial == '.' and token != '.' and token != '...')):
|
|
yield TokenInfo(NUMBER, token, spos, epos, line)
|
|
elif initial in '\r\n':
|
|
yield TokenInfo(NL if parenlev > 0 else NEWLINE,
|
|
token, spos, epos, line)
|
|
elif initial == '#':
|
|
assert not token.endswith("\n")
|
|
yield TokenInfo(COMMENT, token, spos, epos, line)
|
|
elif token in triple_quoted:
|
|
endprog = endprogs[token]
|
|
endmatch = endprog.match(line, pos)
|
|
if endmatch: # all on one line
|
|
pos = endmatch.end(0)
|
|
token = line[start:pos]
|
|
yield TokenInfo(STRING, token, spos, (lnum, pos), line)
|
|
else:
|
|
strstart = (lnum, start) # multiple lines
|
|
contstr = line[start:]
|
|
contline = line
|
|
break
|
|
elif initial in single_quoted or \
|
|
token[:2] in single_quoted or \
|
|
token[:3] in single_quoted:
|
|
if token[-1] == '\n': # continued string
|
|
strstart = (lnum, start)
|
|
endprog = (endprogs[initial] or endprogs[token[1]] or
|
|
endprogs[token[2]])
|
|
contstr, needcont = line[start:], 1
|
|
contline = line
|
|
break
|
|
else: # ordinary string
|
|
yield TokenInfo(STRING, token, spos, epos, line)
|
|
elif initial.isidentifier(): # ordinary name
|
|
yield TokenInfo(NAME, token, spos, epos, line)
|
|
elif initial == '\\': # continued stmt
|
|
continued = 1
|
|
else:
|
|
if initial in '([{':
|
|
parenlev += 1
|
|
elif initial in ')]}':
|
|
parenlev -= 1
|
|
yield TokenInfo(OP, token, spos, epos, line)
|
|
else:
|
|
yield TokenInfo(ERRORTOKEN, line[pos],
|
|
(lnum, pos), (lnum, pos+1), line)
|
|
pos += 1
|
|
|
|
for indent in indents[1:]: # pop remaining indent levels
|
|
yield TokenInfo(DEDENT, '', (lnum, 0), (lnum, 0), '')
|
|
yield TokenInfo(ENDMARKER, '', (lnum, 0), (lnum, 0), '')
|
|
|
|
|
|
# An undocumented, backwards compatible, API for all the places in the standard
|
|
# library that expect to be able to use tokenize with strings
|
|
def generate_tokens(readline):
|
|
return _tokenize(readline, None)
|