1 | """Record of phased-in incompatible language changes.
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2 |
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3 | Each line is of the form:
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4 |
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5 | FeatureName = "_Feature(" OptionalRelease "," MandatoryRelease ","
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6 | CompilerFlag ")"
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7 |
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8 | where, normally, OptionalRelease < MandatoryRelease, and both are 5-tuples
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9 | of the same form as sys.version_info:
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10 |
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11 | (PY_MAJOR_VERSION, # the 2 in 2.1.0a3; an int
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12 | PY_MINOR_VERSION, # the 1; an int
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13 | PY_MICRO_VERSION, # the 0; an int
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14 | PY_RELEASE_LEVEL, # "alpha", "beta", "candidate" or "final"; string
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15 | PY_RELEASE_SERIAL # the 3; an int
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16 | )
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17 |
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18 | OptionalRelease records the first release in which
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19 |
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20 | from __future__ import FeatureName
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21 |
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22 | was accepted.
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23 |
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24 | In the case of MandatoryReleases that have not yet occurred,
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25 | MandatoryRelease predicts the release in which the feature will become part
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26 | of the language.
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27 |
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28 | Else MandatoryRelease records when the feature became part of the language;
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29 | in releases at or after that, modules no longer need
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30 |
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31 | from __future__ import FeatureName
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32 |
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33 | to use the feature in question, but may continue to use such imports.
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34 |
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35 | MandatoryRelease may also be None, meaning that a planned feature got
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36 | dropped.
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37 |
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38 | Instances of class _Feature have two corresponding methods,
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39 | .getOptionalRelease() and .getMandatoryRelease().
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40 |
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41 | CompilerFlag is the (bitfield) flag that should be passed in the fourth
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42 | argument to the builtin function compile() to enable the feature in
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43 | dynamically compiled code. This flag is stored in the .compiler_flag
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44 | attribute on _Future instances. These values must match the appropriate
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45 | #defines of CO_xxx flags in Include/compile.h.
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46 |
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47 | No feature line is ever to be deleted from this file.
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48 | """
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49 |
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50 | all_feature_names = [
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51 | "nested_scopes",
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52 | "generators",
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53 | "division",
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54 | "absolute_import",
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55 | "with_statement",
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56 | "print_function",
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57 | "unicode_literals",
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58 | ]
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59 |
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60 | __all__ = ["all_feature_names"] + all_feature_names
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61 |
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62 | # The CO_xxx symbols are defined here under the same names used by
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63 | # compile.h, so that an editor search will find them here. However,
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64 | # they're not exported in __all__, because they don't really belong to
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65 | # this module.
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66 | CO_NESTED = 0x0010 # nested_scopes
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67 | CO_GENERATOR_ALLOWED = 0 # generators (obsolete, was 0x1000)
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68 | CO_FUTURE_DIVISION = 0x2000 # division
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69 | CO_FUTURE_ABSOLUTE_IMPORT = 0x4000 # perform absolute imports by default
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70 | CO_FUTURE_WITH_STATEMENT = 0x8000 # with statement
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71 | CO_FUTURE_PRINT_FUNCTION = 0x10000 # print function
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72 | CO_FUTURE_UNICODE_LITERALS = 0x20000 # unicode string literals
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73 |
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74 | class _Feature:
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75 | def __init__(self, optionalRelease, mandatoryRelease, compiler_flag):
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76 | self.optional = optionalRelease
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77 | self.mandatory = mandatoryRelease
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78 | self.compiler_flag = compiler_flag
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79 |
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80 | def getOptionalRelease(self):
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81 | """Return first release in which this feature was recognized.
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82 |
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83 | This is a 5-tuple, of the same form as sys.version_info.
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84 | """
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85 |
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86 | return self.optional
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87 |
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88 | def getMandatoryRelease(self):
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89 | """Return release in which this feature will become mandatory.
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90 |
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91 | This is a 5-tuple, of the same form as sys.version_info, or, if
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92 | the feature was dropped, is None.
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93 | """
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94 |
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95 | return self.mandatory
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96 |
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97 | def __repr__(self):
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98 | return "_Feature" + repr((self.optional,
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99 | self.mandatory,
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100 | self.compiler_flag))
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101 |
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102 | nested_scopes = _Feature((2, 1, 0, "beta", 1),
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103 | (2, 2, 0, "alpha", 0),
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104 | CO_NESTED)
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105 |
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106 | generators = _Feature((2, 2, 0, "alpha", 1),
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107 | (2, 3, 0, "final", 0),
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108 | CO_GENERATOR_ALLOWED)
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109 |
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110 | division = _Feature((2, 2, 0, "alpha", 2),
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111 | (3, 0, 0, "alpha", 0),
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112 | CO_FUTURE_DIVISION)
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113 |
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114 | absolute_import = _Feature((2, 5, 0, "alpha", 1),
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115 | (3, 0, 0, "alpha", 0),
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116 | CO_FUTURE_ABSOLUTE_IMPORT)
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117 |
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118 | with_statement = _Feature((2, 5, 0, "alpha", 1),
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119 | (2, 6, 0, "alpha", 0),
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120 | CO_FUTURE_WITH_STATEMENT)
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121 |
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122 | print_function = _Feature((2, 6, 0, "alpha", 2),
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123 | (3, 0, 0, "alpha", 0),
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124 | CO_FUTURE_PRINT_FUNCTION)
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125 |
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126 | unicode_literals = _Feature((2, 6, 0, "alpha", 2),
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127 | (3, 0, 0, "alpha", 0),
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128 | CO_FUTURE_UNICODE_LITERALS)
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