1 """Record of phased-in incompatible language changes. 2 3 Each line is of the form: 4 5 FeatureName = "_Feature(" OptionalRelease "," MandatoryRelease "," 6 CompilerFlag ")" 7 8 where, normally, OptionalRelease < MandatoryRelease, and both are 5-tuples 9 of the same form as sys.version_info: 10 11 (PY_MAJOR_VERSION, # the 2 in 2.1.0a3; an int 12 PY_MINOR_VERSION, # the 1; an int 13 PY_MICRO_VERSION, # the 0; an int 14 PY_RELEASE_LEVEL, # "alpha", "beta", "candidate" or "final"; string 15 PY_RELEASE_SERIAL # the 3; an int 16 ) 17 18 OptionalRelease records the first release in which 19 20 from __future__ import FeatureName 21 22 was accepted. 23 24 In the case of MandatoryReleases that have not yet occurred, 25 MandatoryRelease predicts the release in which the feature will become part 26 of the language. 27 28 Else MandatoryRelease records when the feature became part of the language; 29 in releases at or after that, modules no longer need 30 31 from __future__ import FeatureName 32 33 to use the feature in question, but may continue to use such imports. 34 35 MandatoryRelease may also be None, meaning that a planned feature got 36 dropped. 37 38 Instances of class _Feature have two corresponding methods, 39 .getOptionalRelease() and .getMandatoryRelease(). 40 41 CompilerFlag is the (bitfield) flag that should be passed in the fourth 42 argument to the builtin function compile() to enable the feature in 43 dynamically compiled code. This flag is stored in the .compiler_flag 44 attribute on _Future instances. These values must match the appropriate 45 #defines of CO_xxx flags in Include/compile.h. 46 47 No feature line is ever to be deleted from this file. 48 """ 49 50 all_feature_names = [ 51 "nested_scopes", 52 "generators", 53 "division", 54 "absolute_import", 55 "with_statement", 56 "print_function", 57 "unicode_literals", 58 ] 59 60 __all__ = ["all_feature_names"] + all_feature_names 61 62 # The CO_xxx symbols are defined here under the same names used by 63 # compile.h, so that an editor search will find them here. However, 64 # they're not exported in __all__, because they don't really belong to 65 # this module. 66 CO_NESTED = 0x0010 # nested_scopes 67 CO_GENERATOR_ALLOWED = 0 # generators (obsolete, was 0x1000) 68 CO_FUTURE_DIVISION = 0x2000 # division 69 CO_FUTURE_ABSOLUTE_IMPORT = 0x4000 # perform absolute imports by default 70 CO_FUTURE_WITH_STATEMENT = 0x8000 # with statement 71 CO_FUTURE_PRINT_FUNCTION = 0x10000 # print function 72 CO_FUTURE_UNICODE_LITERALS = 0x20000 # unicode string literals 73 74 class _Feature: 75 def __init__(self, optionalRelease, mandatoryRelease, compiler_flag): 76 self.optional = optionalRelease 77 self.mandatory = mandatoryRelease 78 self.compiler_flag = compiler_flag 79 80 def getOptionalRelease(self): 81 """Return first release in which this feature was recognized. 82 83 This is a 5-tuple, of the same form as sys.version_info. 84 """ 85 86 return self.optional 87 88 def getMandatoryRelease(self): 89 """Return release in which this feature will become mandatory. 90 91 This is a 5-tuple, of the same form as sys.version_info, or, if 92 the feature was dropped, is None. 93 """ 94 95 return self.mandatory 96 97 def __repr__(self): 98 return "_Feature" + repr((self.optional, 99 self.mandatory, 100 self.compiler_flag)) 101 102 nested_scopes = _Feature((2, 1, 0, "beta", 1), 103 (2, 2, 0, "alpha", 0), 104 CO_NESTED) 105 106 generators = _Feature((2, 2, 0, "alpha", 1), 107 (2, 3, 0, "final", 0), 108 CO_GENERATOR_ALLOWED) 109 110 division = _Feature((2, 2, 0, "alpha", 2), 111 (3, 0, 0, "alpha", 0), 112 CO_FUTURE_DIVISION) 113 114 absolute_import = _Feature((2, 5, 0, "alpha", 1), 115 (3, 0, 0, "alpha", 0), 116 CO_FUTURE_ABSOLUTE_IMPORT) 117 118 with_statement = _Feature((2, 5, 0, "alpha", 1), 119 (2, 6, 0, "alpha", 0), 120 CO_FUTURE_WITH_STATEMENT) 121 122 print_function = _Feature((2, 6, 0, "alpha", 2), 123 (3, 0, 0, "alpha", 0), 124 CO_FUTURE_PRINT_FUNCTION) 125 126 unicode_literals = _Feature((2, 6, 0, "alpha", 2), 127 (3, 0, 0, "alpha", 0), 128 CO_FUTURE_UNICODE_LITERALS) 129
