| 1 | """Tokenization help for Python programs.
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| 2 |
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| 3 | generate_tokens(readline) is a generator that breaks a stream of
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| 4 | text into Python tokens. It accepts a readline-like method which is called
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| 5 | repeatedly to get the next line of input (or "" for EOF). It generates
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| 6 | 5-tuples with these members:
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| 7 |
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| 8 | the token type (see token.py)
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| 9 | the token (a string)
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| 10 | the starting (row, column) indices of the token (a 2-tuple of ints)
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| 11 | the ending (row, column) indices of the token (a 2-tuple of ints)
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| 12 | the original line (string)
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| 13 |
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| 14 | It is designed to match the working of the Python tokenizer exactly, except
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| 15 | that it produces COMMENT tokens for comments and gives type OP for all
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| 16 | operators
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| 17 |
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| 18 | Older entry points
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| 19 | tokenize_loop(readline, tokeneater)
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| 20 | tokenize(readline, tokeneater=printtoken)
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| 21 | are the same, except instead of generating tokens, tokeneater is a callback
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| 22 | function to which the 5 fields described above are passed as 5 arguments,
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| 23 | each time a new token is found."""
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| 24 |
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| 25 | __author__ = 'Ka-Ping Yee <ping@lfw.org>'
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| 26 | __credits__ = \
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| 27 | 'GvR, ESR, Tim Peters, Thomas Wouters, Fred Drake, Skip Montanaro'
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| 28 |
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| 29 | import string, re
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| 30 | from token import *
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| 31 |
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| 32 | import token
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| 33 | __all__ = [x for x in dir(token) if x[0] != '_'] + ["COMMENT", "tokenize",
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| 34 | "generate_tokens", "NL", "untokenize"]
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| 35 | del x
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| 36 | del token
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| 37 |
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| 38 | COMMENT = N_TOKENS
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| 39 | tok_name[COMMENT] = 'COMMENT'
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| 40 | NL = N_TOKENS + 1
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| 41 | tok_name[NL] = 'NL'
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| 42 | N_TOKENS += 2
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| 43 |
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| 44 | def group(*choices): return '(' + '|'.join(choices) + ')'
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| 45 | def any(*choices): return group(*choices) + '*'
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| 46 | def maybe(*choices): return group(*choices) + '?'
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| 47 |
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| 48 | Whitespace = r'[ \f\t]*'
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| 49 | Comment = r'#[^\r\n]*'
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| 50 | Ignore = Whitespace + any(r'\\\r?\n' + Whitespace) + maybe(Comment)
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| 51 | Name = r'[a-zA-Z_]\w*'
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| 52 |
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| 53 | Hexnumber = r'0[xX][\da-fA-F]*[lL]?'
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| 54 | Octnumber = r'0[0-7]*[lL]?'
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| 55 | Decnumber = r'[1-9]\d*[lL]?'
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| 56 | Intnumber = group(Hexnumber, Octnumber, Decnumber)
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| 57 | Exponent = r'[eE][-+]?\d+'
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| 58 | Pointfloat = group(r'\d+\.\d*', r'\.\d+') + maybe(Exponent)
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| 59 | Expfloat = r'\d+' + Exponent
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| 60 | Floatnumber = group(Pointfloat, Expfloat)
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| 61 | Imagnumber = group(r'\d+[jJ]', Floatnumber + r'[jJ]')
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| 62 | Number = group(Imagnumber, Floatnumber, Intnumber)
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| 63 |
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| 64 | # Tail end of ' string.
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| 65 | Single = r"[^'\\]*(?:\\.[^'\\]*)*'"
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| 66 | # Tail end of " string.
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| 67 | Double = r'[^"\\]*(?:\\.[^"\\]*)*"'
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| 68 | # Tail end of ''' string.
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| 69 | Single3 = r"[^'\\]*(?:(?:\\.|'(?!''))[^'\\]*)*'''"
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| 70 | # Tail end of """ string.
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| 71 | Double3 = r'[^"\\]*(?:(?:\\.|"(?!""))[^"\\]*)*"""'
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| 72 | Triple = group("[uU]?[rR]?'''", '[uU]?[rR]?"""')
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| 73 | # Single-line ' or " string.
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| 74 | String = group(r"[uU]?[rR]?'[^\n'\\]*(?:\\.[^\n'\\]*)*'",
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| 75 | r'[uU]?[rR]?"[^\n"\\]*(?:\\.[^\n"\\]*)*"')
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| 76 |
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| 77 | # Because of leftmost-then-longest match semantics, be sure to put the
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| 78 | # longest operators first (e.g., if = came before ==, == would get
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| 79 | # recognized as two instances of =).
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| 80 | Operator = group(r"\*\*=?", r">>=?", r"<<=?", r"<>", r"!=",
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| 81 | r"//=?",
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| 82 | r"[+\-*/%&|^=<>]=?",
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| 83 | r"~")
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| 84 |
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| 85 | Bracket = '[][(){}]'
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| 86 | Special = group(r'\r?\n', r'[:;.,`@]')
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| 87 | Funny = group(Operator, Bracket, Special)
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| 88 |
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| 89 | PlainToken = group(Number, Funny, String, Name)
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| 90 | Token = Ignore + PlainToken
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| 91 |
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| 92 | # First (or only) line of ' or " string.
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| 93 | ContStr = group(r"[uU]?[rR]?'[^\n'\\]*(?:\\.[^\n'\\]*)*" +
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| 94 | group("'", r'\\\r?\n'),
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| 95 | r'[uU]?[rR]?"[^\n"\\]*(?:\\.[^\n"\\]*)*' +
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| 96 | group('"', r'\\\r?\n'))
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| 97 | PseudoExtras = group(r'\\\r?\n', Comment, Triple)
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| 98 | PseudoToken = Whitespace + group(PseudoExtras, Number, Funny, ContStr, Name)
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| 99 |
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| 100 | tokenprog, pseudoprog, single3prog, double3prog = map(
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| 101 | re.compile, (Token, PseudoToken, Single3, Double3))
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| 102 | endprogs = {"'": re.compile(Single), '"': re.compile(Double),
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| 103 | "'''": single3prog, '"""': double3prog,
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| 104 | "r'''": single3prog, 'r"""': double3prog,
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| 105 | "u'''": single3prog, 'u"""': double3prog,
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| 106 | "ur'''": single3prog, 'ur"""': double3prog,
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| 107 | "R'''": single3prog, 'R"""': double3prog,
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| 108 | "U'''": single3prog, 'U"""': double3prog,
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| 109 | "uR'''": single3prog, 'uR"""': double3prog,
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| 110 | "Ur'''": single3prog, 'Ur"""': double3prog,
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| 111 | "UR'''": single3prog, 'UR"""': double3prog,
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| 112 | 'r': None, 'R': None, 'u': None, 'U': None}
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| 113 |
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| 114 | triple_quoted = {}
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| 115 | for t in ("'''", '"""',
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| 116 | "r'''", 'r"""', "R'''", 'R"""',
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| 117 | "u'''", 'u"""', "U'''", 'U"""',
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| 118 | "ur'''", 'ur"""', "Ur'''", 'Ur"""',
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| 119 | "uR'''", 'uR"""', "UR'''", 'UR"""'):
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| 120 | triple_quoted[t] = t
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| 121 | single_quoted = {}
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| 122 | for t in ("'", '"',
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| 123 | "r'", 'r"', "R'", 'R"',
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| 124 | "u'", 'u"', "U'", 'U"',
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| 125 | "ur'", 'ur"', "Ur'", 'Ur"',
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| 126 | "uR'", 'uR"', "UR'", 'UR"' ):
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| 127 | single_quoted[t] = t
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| 128 |
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| 129 | tabsize = 8
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| 130 |
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| 131 | class TokenError(Exception): pass
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| 132 |
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| 133 | class StopTokenizing(Exception): pass
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| 134 |
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| 135 | def printtoken(type, token, (srow, scol), (erow, ecol), line): # for testing
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| 136 | print "%d,%d-%d,%d:\t%s\t%s" % \
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| 137 | (srow, scol, erow, ecol, tok_name[type], repr(token))
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| 138 |
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| 139 | def tokenize(readline, tokeneater=printtoken):
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| 140 | """
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| 141 | The tokenize() function accepts two parameters: one representing the
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| 142 | input stream, and one providing an output mechanism for tokenize().
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| 143 |
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| 144 | The first parameter, readline, must be a callable object which provides
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| 145 | the same interface as the readline() method of built-in file objects.
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| 146 | Each call to the function should return one line of input as a string.
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| 147 |
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| 148 | The second parameter, tokeneater, must also be a callable object. It is
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| 149 | called once for each token, with five arguments, corresponding to the
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| 150 | tuples generated by generate_tokens().
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| 151 | """
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| 152 | try:
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| 153 | tokenize_loop(readline, tokeneater)
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| 154 | except StopTokenizing:
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| 155 | pass
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| 156 |
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| 157 | # backwards compatible interface
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| 158 | def tokenize_loop(readline, tokeneater):
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| 159 | for token_info in generate_tokens(readline):
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| 160 | tokeneater(*token_info)
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| 161 |
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| 162 |
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| 163 | def untokenize(iterable):
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| 164 | """Transform tokens back into Python source code.
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| 165 |
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| 166 | Each element returned by the iterable must be a token sequence
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| 167 | with at least two elements, a token number and token value.
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| 168 |
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| 169 | Round-trip invariant:
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| 170 | # Output text will tokenize the back to the input
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| 171 | t1 = [tok[:2] for tok in generate_tokens(f.readline)]
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| 172 | newcode = untokenize(t1)
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| 173 | readline = iter(newcode.splitlines(1)).next
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| 174 | t2 = [tok[:2] for tokin generate_tokens(readline)]
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| 175 | assert t1 == t2
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| 176 | """
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| 177 |
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| 178 | startline = False
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| 179 | indents = []
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| 180 | toks = []
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| 181 | toks_append = toks.append
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| 182 | for tok in iterable:
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| 183 | toknum, tokval = tok[:2]
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| 184 |
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| 185 | if toknum in (NAME, NUMBER):
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| 186 | tokval += ' '
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| 187 |
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| 188 | if toknum == INDENT:
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| 189 | indents.append(tokval)
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| 190 | continue
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| 191 | elif toknum == DEDENT:
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| 192 | indents.pop()
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| 193 | continue
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| 194 | elif toknum in (NEWLINE, COMMENT, NL):
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| 195 | startline = True
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| 196 | elif startline and indents:
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| 197 | toks_append(indents[-1])
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| 198 | startline = False
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| 199 | toks_append(tokval)
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| 200 | return ''.join(toks)
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| 201 |
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| 202 |
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| 203 | def generate_tokens(readline):
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| 204 | """
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| 205 | The generate_tokens() generator requires one argment, readline, which
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| 206 | must be a callable object which provides the same interface as the
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| 207 | readline() method of built-in file objects. Each call to the function
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| 208 | should return one line of input as a string. Alternately, readline
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| 209 | can be a callable function terminating with StopIteration:
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| 210 | readline = open(myfile).next # Example of alternate readline
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| 211 |
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| 212 | The generator produces 5-tuples with these members: the token type; the
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| 213 | token string; a 2-tuple (srow, scol) of ints specifying the row and
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| 214 | column where the token begins in the source; a 2-tuple (erow, ecol) of
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| 215 | ints specifying the row and column where the token ends in the source;
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| 216 | and the line on which the token was found. The line passed is the
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| 217 | logical line; continuation lines are included.
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| 218 | """
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| 219 | lnum = parenlev = continued = 0
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| 220 | namechars, numchars = string.ascii_letters + '_', '0123456789'
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| 221 | contstr, needcont = '', 0
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| 222 | contline = None
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| 223 | indents = [0]
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| 224 |
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| 225 | while 1: # loop over lines in stream
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| 226 | try:
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| 227 | line = readline()
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| 228 | except StopIteration:
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| 229 | line = ''
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| 230 | lnum = lnum + 1
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| 231 | pos, max = 0, len(line)
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| 232 |
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| 233 | if contstr: # continued string
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| 234 | if not line:
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| 235 | raise TokenError, ("EOF in multi-line string", strstart)
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| 236 | endmatch = endprog.match(line)
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| 237 | if endmatch:
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| 238 | pos = end = endmatch.end(0)
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| 239 | yield (STRING, contstr + line[:end],
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| 240 | strstart, (lnum, end), contline + line)
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| 241 | contstr, needcont = '', 0
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| 242 | contline = None
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| 243 | elif needcont and line[-2:] != '\\\n' and line[-3:] != '\\\r\n':
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| 244 | yield (ERRORTOKEN, contstr + line,
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| 245 | strstart, (lnum, len(line)), contline)
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| 246 | contstr = ''
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| 247 | contline = None
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| 248 | continue
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| 249 | else:
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| 250 | contstr = contstr + line
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| 251 | contline = contline + line
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| 252 | continue
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| 253 |
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| 254 | elif parenlev == 0 and not continued: # new statement
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| 255 | if not line: break
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| 256 | column = 0
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| 257 | while pos < max: # measure leading whitespace
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| 258 | if line[pos] == ' ': column = column + 1
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| 259 | elif line[pos] == '\t': column = (column/tabsize + 1)*tabsize
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| 260 | elif line[pos] == '\f': column = 0
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| 261 | else: break
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| 262 | pos = pos + 1
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| 263 | if pos == max: break
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| 264 |
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| 265 | if line[pos] in '#\r\n': # skip comments or blank lines
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| 266 | yield ((NL, COMMENT)[line[pos] == '#'], line[pos:],
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| 267 | (lnum, pos), (lnum, len(line)), line)
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| 268 | continue
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| 269 |
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| 270 | if column > indents[-1]: # count indents or dedents
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| 271 | indents.append(column)
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| 272 | yield (INDENT, line[:pos], (lnum, 0), (lnum, pos), line)
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| 273 | while column < indents[-1]:
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| 274 | if column not in indents:
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| 275 | raise IndentationError(
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| 276 | "unindent does not match any outer indentation level",
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| 277 | ("<tokenize>", lnum, pos, line))
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| 278 | indents = indents[:-1]
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| 279 | yield (DEDENT, '', (lnum, pos), (lnum, pos), line)
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| 280 |
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| 281 | else: # continued statement
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| 282 | if not line:
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| 283 | raise TokenError, ("EOF in multi-line statement", (lnum, 0))
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| 284 | continued = 0
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| 285 |
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| 286 | while pos < max:
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| 287 | pseudomatch = pseudoprog.match(line, pos)
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| 288 | if pseudomatch: # scan for tokens
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| 289 | start, end = pseudomatch.span(1)
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| 290 | spos, epos, pos = (lnum, start), (lnum, end), end
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| 291 | token, initial = line[start:end], line[start]
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| 292 |
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| 293 | if initial in numchars or \
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| 294 | (initial == '.' and token != '.'): # ordinary number
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| 295 | yield (NUMBER, token, spos, epos, line)
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| 296 | elif initial in '\r\n':
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| 297 | yield (parenlev > 0 and NL or NEWLINE,
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| 298 | token, spos, epos, line)
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| 299 | elif initial == '#':
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| 300 | yield (COMMENT, token, spos, epos, line)
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| 301 | elif token in triple_quoted:
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| 302 | endprog = endprogs[token]
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| 303 | endmatch = endprog.match(line, pos)
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| 304 | if endmatch: # all on one line
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| 305 | pos = endmatch.end(0)
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| 306 | token = line[start:pos]
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| 307 | yield (STRING, token, spos, (lnum, pos), line)
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| 308 | else:
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| 309 | strstart = (lnum, start) # multiple lines
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| 310 | contstr = line[start:]
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| 311 | contline = line
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| 312 | break
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| 313 | elif initial in single_quoted or \
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| 314 | token[:2] in single_quoted or \
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| 315 | token[:3] in single_quoted:
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| 316 | if token[-1] == '\n': # continued string
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| 317 | strstart = (lnum, start)
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| 318 | endprog = (endprogs[initial] or endprogs[token[1]] or
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| 319 | endprogs[token[2]])
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| 320 | contstr, needcont = line[start:], 1
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| 321 | contline = line
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| 322 | break
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| 323 | else: # ordinary string
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| 324 | yield (STRING, token, spos, epos, line)
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| 325 | elif initial in namechars: # ordinary name
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| 326 | yield (NAME, token, spos, epos, line)
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| 327 | elif initial == '\\': # continued stmt
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| 328 | continued = 1
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| 329 | else:
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| 330 | if initial in '([{': parenlev = parenlev + 1
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| 331 | elif initial in ')]}': parenlev = parenlev - 1
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| 332 | yield (OP, token, spos, epos, line)
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| 333 | else:
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| 334 | yield (ERRORTOKEN, line[pos],
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| 335 | (lnum, pos), (lnum, pos+1), line)
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| 336 | pos = pos + 1
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| 337 |
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| 338 | for indent in indents[1:]: # pop remaining indent levels
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| 339 | yield (DEDENT, '', (lnum, 0), (lnum, 0), '')
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| 340 | yield (ENDMARKER, '', (lnum, 0), (lnum, 0), '')
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| 341 |
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| 342 | if __name__ == '__main__': # testing
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| 343 | import sys
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| 344 | if len(sys.argv) > 1: tokenize(open(sys.argv[1]).readline)
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| 345 | else: tokenize(sys.stdin.readline)
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