mirror of
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fd036451bf
and str (unicode) patterns get full unicode matching by default. The re.ASCII flag is also introduced to ask for ASCII matching instead.
475 lines
17 KiB
Python
475 lines
17 KiB
Python
"""Tokenization help for Python programs.
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tokenize(readline) is a generator that breaks a stream of
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bytes into Python tokens. It decodes the bytes according to
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PEP-0263 for determining source file encoding.
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It accepts a readline-like method which is called
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repeatedly to get the next line of input (or b"" for EOF). It generates
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5-tuples with these 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. Aditionally, 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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__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, string, sys
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from token import *
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from codecs import lookup
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from itertools import chain, repeat
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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 x[0] != '_'] + ["COMMENT", "tokenize",
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"detect_encoding", "NL", "untokenize", "ENCODING"]
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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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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'[a-zA-Z_]\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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tokenprog, pseudoprog, single3prog, double3prog = map(
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re.compile, (Token, PseudoToken, Single3, Double3))
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endprogs = {"'": re.compile(Single), '"': re.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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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 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
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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.
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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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utf8_bom = b'\xef\xbb\xbf'
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bom_found = False
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encoding = None
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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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pass
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else:
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matches = cookie_re.findall(line_string)
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if matches:
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encoding = matches[0]
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if bom_found and lookup(encoding).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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return encoding
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first = read_or_stop()
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if first.startswith(utf8_bom):
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bom_found = True
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first = first[3:]
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if not first:
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return 'utf-8', []
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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 'utf-8', [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 'utf-8', [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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encoding, consumed = detect_encoding(readline)
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def readline_generator():
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while True:
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try:
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yield readline()
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except StopIteration:
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return
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chained = chain(consumed, readline_generator())
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return _tokenize(chained.__next__, encoding)
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def _tokenize(readline, encoding):
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lnum = parenlev = continued = 0
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namechars, numchars = string.ascii_letters + '_', '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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yield (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 = 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 (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 (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] == ' ': column = column + 1
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elif line[pos] == '\t': column = (column/tabsize + 1)*tabsize
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elif line[pos] == '\f': column = 0
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else: break
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pos = pos + 1
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if pos == max: 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 (COMMENT, comment_token,
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(lnum, pos), (lnum, pos + len(comment_token)), line)
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yield (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 ((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 (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 (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)
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if pseudomatch: # scan for tokens
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start, end = pseudomatch.span(1)
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spos, epos, pos = (lnum, start), (lnum, end), end
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token, initial = line[start:end], line[start]
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if (initial in numchars or # ordinary number
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(initial == '.' and token != '.' and token != '...')):
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yield (NUMBER, token, spos, epos, line)
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elif initial in '\r\n':
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yield (NL if parenlev > 0 else NEWLINE,
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token, spos, epos, line)
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elif initial == '#':
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assert not token.endswith("\n")
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yield (COMMENT, token, spos, epos, line)
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elif token in triple_quoted:
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endprog = endprogs[token]
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endmatch = endprog.match(line, pos)
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if endmatch: # all on one line
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pos = endmatch.end(0)
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token = line[start:pos]
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yield (STRING, token, spos, (lnum, pos), line)
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else:
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strstart = (lnum, start) # multiple lines
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contstr = line[start:]
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contline = line
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break
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elif initial in single_quoted or \
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token[:2] in single_quoted or \
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token[:3] in single_quoted:
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if token[-1] == '\n': # continued string
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strstart = (lnum, start)
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endprog = (endprogs[initial] or endprogs[token[1]] or
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endprogs[token[2]])
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contstr, needcont = line[start:], 1
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contline = line
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break
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else: # ordinary string
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yield (STRING, token, spos, epos, line)
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elif initial in namechars: # ordinary name
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yield (NAME, token, spos, epos, line)
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elif initial == '\\': # continued stmt
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continued = 1
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else:
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if initial in '([{': parenlev = parenlev + 1
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elif initial in ')]}': parenlev = parenlev - 1
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yield (OP, token, spos, epos, line)
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else:
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yield (ERRORTOKEN, line[pos],
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(lnum, pos), (lnum, pos+1), line)
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pos = pos + 1
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for indent in indents[1:]: # pop remaining indent levels
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yield (DEDENT, '', (lnum, 0), (lnum, 0), '')
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yield (ENDMARKER, '', (lnum, 0), (lnum, 0), '')
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# An undocumented, backwards compatible, API for all the places in the standard
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# library that expect to be able to use tokenize with strings
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def generate_tokens(readline):
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return _tokenize(readline, None)
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