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__ = ('GvR, ESR, Tim Peters, Thomas Wouters, Fred Drake, '
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27 | 'Skip Montanaro, Raymond Hettinger')
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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 not x.startswith("_")]
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34 | __all__ += ["COMMENT", "tokenize", "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[oO][0-7]+)|(0[0-7]*)[lL]?'
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55 | Binnumber = r'0[bB][01]+[lL]?'
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56 | Decnumber = r'[1-9]\d*[lL]?'
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57 | Intnumber = group(Hexnumber, Binnumber, Octnumber, Decnumber)
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58 | Exponent = r'[eE][-+]?\d+'
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59 | Pointfloat = group(r'\d+\.\d*', r'\.\d+') + maybe(Exponent)
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60 | Expfloat = r'\d+' + Exponent
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61 | Floatnumber = group(Pointfloat, Expfloat)
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62 | Imagnumber = group(r'\d+[jJ]', Floatnumber + r'[jJ]')
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63 | Number = group(Imagnumber, Floatnumber, Intnumber)
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64 |
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65 | # Tail end of ' string.
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66 | Single = r"[^'\\]*(?:\\.[^'\\]*)*'"
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67 | # Tail end of " string.
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68 | Double = r'[^"\\]*(?:\\.[^"\\]*)*"'
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69 | # Tail end of ''' string.
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70 | Single3 = r"[^'\\]*(?:(?:\\.|'(?!''))[^'\\]*)*'''"
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71 | # Tail end of """ string.
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72 | Double3 = r'[^"\\]*(?:(?:\\.|"(?!""))[^"\\]*)*"""'
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73 | Triple = group("[uUbB]?[rR]?'''", '[uUbB]?[rR]?"""')
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74 | # Single-line ' or " string.
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75 | String = group(r"[uUbB]?[rR]?'[^\n'\\]*(?:\\.[^\n'\\]*)*'",
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76 | r'[uUbB]?[rR]?"[^\n"\\]*(?:\\.[^\n"\\]*)*"')
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77 |
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78 | # Because of leftmost-then-longest match semantics, be sure to put the
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79 | # longest operators first (e.g., if = came before ==, == would get
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80 | # recognized as two instances of =).
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81 | Operator = group(r"\*\*=?", r">>=?", r"<<=?", r"<>", r"!=",
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82 | r"//=?",
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83 | r"[+\-*/%&|^=<>]=?",
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84 | r"~")
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85 |
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86 | Bracket = '[][(){}]'
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87 | Special = group(r'\r?\n', r'[:;.,`@]')
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88 | Funny = group(Operator, Bracket, Special)
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89 |
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90 | PlainToken = group(Number, Funny, String, Name)
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91 | Token = Ignore + PlainToken
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92 |
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93 | # First (or only) line of ' or " string.
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94 | ContStr = group(r"[uUbB]?[rR]?'[^\n'\\]*(?:\\.[^\n'\\]*)*" +
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95 | group("'", r'\\\r?\n'),
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96 | r'[uUbB]?[rR]?"[^\n"\\]*(?:\\.[^\n"\\]*)*' +
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97 | group('"', r'\\\r?\n'))
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98 | PseudoExtras = group(r'\\\r?\n|\Z', Comment, Triple)
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99 | PseudoToken = Whitespace + group(PseudoExtras, Number, Funny, ContStr, Name)
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100 |
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101 | tokenprog, pseudoprog, single3prog, double3prog = map(
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102 | re.compile, (Token, PseudoToken, Single3, Double3))
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103 | endprogs = {"'": re.compile(Single), '"': re.compile(Double),
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104 | "'''": single3prog, '"""': double3prog,
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105 | "r'''": single3prog, 'r"""': double3prog,
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106 | "u'''": single3prog, 'u"""': double3prog,
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107 | "ur'''": single3prog, 'ur"""': double3prog,
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108 | "R'''": single3prog, 'R"""': double3prog,
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109 | "U'''": single3prog, 'U"""': double3prog,
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110 | "uR'''": single3prog, 'uR"""': double3prog,
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111 | "Ur'''": single3prog, 'Ur"""': double3prog,
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112 | "UR'''": single3prog, 'UR"""': double3prog,
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113 | "b'''": single3prog, 'b"""': double3prog,
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114 | "br'''": single3prog, 'br"""': double3prog,
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115 | "B'''": single3prog, 'B"""': double3prog,
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116 | "bR'''": single3prog, 'bR"""': double3prog,
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117 | "Br'''": single3prog, 'Br"""': double3prog,
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118 | "BR'''": single3prog, 'BR"""': double3prog,
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119 | 'r': None, 'R': None, 'u': None, 'U': None,
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120 | 'b': None, 'B': None}
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121 |
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122 | triple_quoted = {}
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123 | for t in ("'''", '"""',
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124 | "r'''", 'r"""', "R'''", 'R"""',
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125 | "u'''", 'u"""', "U'''", 'U"""',
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126 | "ur'''", 'ur"""', "Ur'''", 'Ur"""',
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127 | "uR'''", 'uR"""', "UR'''", 'UR"""',
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128 | "b'''", 'b"""', "B'''", 'B"""',
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129 | "br'''", 'br"""', "Br'''", 'Br"""',
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130 | "bR'''", 'bR"""', "BR'''", 'BR"""'):
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131 | triple_quoted[t] = t
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132 | single_quoted = {}
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133 | for t in ("'", '"',
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134 | "r'", 'r"', "R'", 'R"',
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135 | "u'", 'u"', "U'", 'U"',
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136 | "ur'", 'ur"', "Ur'", 'Ur"',
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137 | "uR'", 'uR"', "UR'", 'UR"',
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138 | "b'", 'b"', "B'", 'B"',
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139 | "br'", 'br"', "Br'", 'Br"',
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140 | "bR'", 'bR"', "BR'", 'BR"' ):
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141 | single_quoted[t] = t
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142 |
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143 | tabsize = 8
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144 |
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145 | class TokenError(Exception): pass
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146 |
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147 | class StopTokenizing(Exception): pass
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148 |
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149 | def printtoken(type, token, srow_scol, erow_ecol, line): # for testing
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150 | srow, scol = srow_scol
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151 | erow, ecol = erow_ecol
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152 | print "%d,%d-%d,%d:\t%s\t%s" % \
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153 | (srow, scol, erow, ecol, tok_name[type], repr(token))
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154 |
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155 | def tokenize(readline, tokeneater=printtoken):
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156 | """
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157 | The tokenize() function accepts two parameters: one representing the
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158 | input stream, and one providing an output mechanism for tokenize().
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159 |
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160 | The first parameter, readline, must be a callable object which provides
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161 | the same interface as the readline() method of built-in file objects.
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162 | Each call to the function should return one line of input as a string.
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163 |
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164 | The second parameter, tokeneater, must also be a callable object. It is
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165 | called once for each token, with five arguments, corresponding to the
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166 | tuples generated by generate_tokens().
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167 | """
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168 | try:
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169 | tokenize_loop(readline, tokeneater)
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170 | except StopTokenizing:
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171 | pass
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172 |
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173 | # backwards compatible interface
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174 | def tokenize_loop(readline, tokeneater):
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175 | for token_info in generate_tokens(readline):
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176 | tokeneater(*token_info)
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177 |
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178 | class Untokenizer:
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179 |
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180 | def __init__(self):
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181 | self.tokens = []
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182 | self.prev_row = 1
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183 | self.prev_col = 0
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184 |
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185 | def add_whitespace(self, start):
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186 | row, col = start
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187 | assert row <= self.prev_row
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188 | col_offset = col - self.prev_col
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189 | if col_offset:
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190 | self.tokens.append(" " * col_offset)
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191 |
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192 | def untokenize(self, iterable):
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193 | for t in iterable:
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194 | if len(t) == 2:
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195 | self.compat(t, iterable)
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196 | break
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197 | tok_type, token, start, end, line = t
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198 | self.add_whitespace(start)
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199 | self.tokens.append(token)
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200 | self.prev_row, self.prev_col = end
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201 | if tok_type in (NEWLINE, NL):
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202 | self.prev_row += 1
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203 | self.prev_col = 0
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204 | return "".join(self.tokens)
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205 |
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206 | def compat(self, token, iterable):
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207 | startline = False
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208 | indents = []
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209 | toks_append = self.tokens.append
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210 | toknum, tokval = token
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211 | if toknum in (NAME, NUMBER):
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212 | tokval += ' '
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213 | if toknum in (NEWLINE, NL):
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214 | startline = True
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215 | prevstring = False
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216 | for tok in iterable:
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217 | toknum, tokval = tok[:2]
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218 |
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219 | if toknum in (NAME, NUMBER):
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220 | tokval += ' '
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221 |
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222 | # Insert a space between two consecutive strings
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223 | if toknum == STRING:
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224 | if prevstring:
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225 | tokval = ' ' + tokval
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226 | prevstring = True
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227 | else:
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228 | prevstring = False
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229 |
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230 | if toknum == INDENT:
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231 | indents.append(tokval)
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232 | continue
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233 | elif toknum == DEDENT:
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234 | indents.pop()
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235 | continue
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236 | elif toknum in (NEWLINE, NL):
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237 | startline = True
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238 | elif startline and indents:
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239 | toks_append(indents[-1])
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240 | startline = False
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241 | toks_append(tokval)
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242 |
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243 | def untokenize(iterable):
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244 | """Transform tokens back into Python source code.
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245 |
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246 | Each element returned by the iterable must be a token sequence
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247 | with at least two elements, a token number and token value. If
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248 | only two tokens are passed, the resulting output is poor.
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249 |
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250 | Round-trip invariant for full input:
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251 | Untokenized source will match input source exactly
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252 |
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253 | Round-trip invariant for limited intput:
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254 | # Output text will tokenize the back to the input
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255 | t1 = [tok[:2] for tok in generate_tokens(f.readline)]
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256 | newcode = untokenize(t1)
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257 | readline = iter(newcode.splitlines(1)).next
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258 | t2 = [tok[:2] for tok in generate_tokens(readline)]
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259 | assert t1 == t2
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260 | """
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261 | ut = Untokenizer()
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262 | return ut.untokenize(iterable)
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263 |
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264 | def generate_tokens(readline):
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265 | """
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266 | The generate_tokens() generator requires one argment, readline, which
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267 | must be a callable object which provides the same interface as the
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268 | readline() method of built-in file objects. Each call to the function
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269 | should return one line of input as a string. Alternately, readline
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270 | can be a callable function terminating with StopIteration:
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271 | readline = open(myfile).next # Example of alternate readline
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272 |
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273 | The generator produces 5-tuples with these members: the token type; the
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274 | token string; a 2-tuple (srow, scol) of ints specifying the row and
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275 | column where the token begins in the source; a 2-tuple (erow, ecol) of
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276 | ints specifying the row and column where the token ends in the source;
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277 | and the line on which the token was found. The line passed is the
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278 | logical line; continuation lines are included.
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279 | """
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280 | lnum = parenlev = continued = 0
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281 | namechars, numchars = string.ascii_letters + '_', '0123456789'
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282 | contstr, needcont = '', 0
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283 | contline = None
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284 | indents = [0]
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285 |
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286 | while 1: # loop over lines in stream
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287 | try:
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288 | line = readline()
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289 | except StopIteration:
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290 | line = ''
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291 | lnum += 1
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292 | pos, max = 0, len(line)
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293 |
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294 | if contstr: # continued string
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295 | if not line:
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296 | raise TokenError, ("EOF in multi-line string", strstart)
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297 | endmatch = endprog.match(line)
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298 | if endmatch:
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299 | pos = end = endmatch.end(0)
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300 | yield (STRING, contstr + line[:end],
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301 | strstart, (lnum, end), contline + line)
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302 | contstr, needcont = '', 0
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303 | contline = None
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304 | elif needcont and line[-2:] != '\\\n' and line[-3:] != '\\\r\n':
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305 | yield (ERRORTOKEN, contstr + line,
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306 | strstart, (lnum, len(line)), contline)
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307 | contstr = ''
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308 | contline = None
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309 | continue
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310 | else:
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311 | contstr = contstr + line
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312 | contline = contline + line
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313 | continue
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314 |
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315 | elif parenlev == 0 and not continued: # new statement
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316 | if not line: break
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317 | column = 0
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318 | while pos < max: # measure leading whitespace
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319 | if line[pos] == ' ':
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320 | column += 1
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321 | elif line[pos] == '\t':
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322 | column = (column//tabsize + 1)*tabsize
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323 | elif line[pos] == '\f':
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324 | column = 0
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325 | else:
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326 | break
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327 | pos += 1
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328 | if pos == max:
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329 | break
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330 |
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331 | if line[pos] in '#\r\n': # skip comments or blank lines
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332 | if line[pos] == '#':
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333 | comment_token = line[pos:].rstrip('\r\n')
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334 | nl_pos = pos + len(comment_token)
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335 | yield (COMMENT, comment_token,
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336 | (lnum, pos), (lnum, pos + len(comment_token)), line)
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337 | yield (NL, line[nl_pos:],
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338 | (lnum, nl_pos), (lnum, len(line)), line)
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339 | else:
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340 | yield ((NL, COMMENT)[line[pos] == '#'], line[pos:],
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341 | (lnum, pos), (lnum, len(line)), line)
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342 | continue
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343 |
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344 | if column > indents[-1]: # count indents or dedents
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345 | indents.append(column)
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346 | yield (INDENT, line[:pos], (lnum, 0), (lnum, pos), line)
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347 | while column < indents[-1]:
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348 | if column not in indents:
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349 | raise IndentationError(
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350 | "unindent does not match any outer indentation level",
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351 | ("<tokenize>", lnum, pos, line))
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352 | indents = indents[:-1]
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353 | yield (DEDENT, '', (lnum, pos), (lnum, pos), line)
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354 |
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355 | else: # continued statement
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356 | if not line:
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357 | raise TokenError, ("EOF in multi-line statement", (lnum, 0))
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358 | continued = 0
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359 |
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360 | while pos < max:
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361 | pseudomatch = pseudoprog.match(line, pos)
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362 | if pseudomatch: # scan for tokens
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363 | start, end = pseudomatch.span(1)
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364 | spos, epos, pos = (lnum, start), (lnum, end), end
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365 | if start == end:
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366 | continue
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367 | token, initial = line[start:end], line[start]
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368 |
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369 | if initial in numchars or \
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370 | (initial == '.' and token != '.'): # ordinary number
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371 | yield (NUMBER, token, spos, epos, line)
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372 | elif initial in '\r\n':
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373 | yield (NL if parenlev > 0 else NEWLINE,
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374 | token, spos, epos, line)
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375 | elif initial == '#':
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376 | assert not token.endswith("\n")
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377 | yield (COMMENT, token, spos, epos, line)
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378 | elif token in triple_quoted:
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379 | endprog = endprogs[token]
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380 | endmatch = endprog.match(line, pos)
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381 | if endmatch: # all on one line
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382 | pos = endmatch.end(0)
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383 | token = line[start:pos]
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384 | yield (STRING, token, spos, (lnum, pos), line)
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385 | else:
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386 | strstart = (lnum, start) # multiple lines
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387 | contstr = line[start:]
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388 | contline = line
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389 | break
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390 | elif initial in single_quoted or \
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391 | token[:2] in single_quoted or \
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392 | token[:3] in single_quoted:
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393 | if token[-1] == '\n': # continued string
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394 | strstart = (lnum, start)
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395 | endprog = (endprogs[initial] or endprogs[token[1]] or
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396 | endprogs[token[2]])
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397 | contstr, needcont = line[start:], 1
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398 | contline = line
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399 | break
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400 | else: # ordinary string
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401 | yield (STRING, token, spos, epos, line)
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402 | elif initial in namechars: # ordinary name
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403 | yield (NAME, token, spos, epos, line)
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404 | elif initial == '\\': # continued stmt
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405 | continued = 1
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406 | else:
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407 | if initial in '([{':
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408 | parenlev += 1
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409 | elif initial in ')]}':
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410 | parenlev -= 1
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411 | yield (OP, token, spos, epos, line)
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412 | else:
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413 | yield (ERRORTOKEN, line[pos],
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414 | (lnum, pos), (lnum, pos+1), line)
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415 | pos += 1
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416 |
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417 | for indent in indents[1:]: # pop remaining indent levels
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418 | yield (DEDENT, '', (lnum, 0), (lnum, 0), '')
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419 | yield (ENDMARKER, '', (lnum, 0), (lnum, 0), '')
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420 |
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421 | if __name__ == '__main__': # testing
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422 | import sys
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423 | if len(sys.argv) > 1:
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424 | tokenize(open(sys.argv[1]).readline)
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425 | else:
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426 | tokenize(sys.stdin.readline)
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