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Diffstat (limited to 'lib/python2.7/__future__.py')
-rw-r--r-- | lib/python2.7/__future__.py | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/lib/python2.7/__future__.py b/lib/python2.7/__future__.py new file mode 100644 index 0000000..e0996eb --- /dev/null +++ b/lib/python2.7/__future__.py @@ -0,0 +1,128 @@ +"""Record of phased-in incompatible language changes. + +Each line is of the form: + + FeatureName = "_Feature(" OptionalRelease "," MandatoryRelease "," + CompilerFlag ")" + +where, normally, OptionalRelease < MandatoryRelease, and both are 5-tuples +of the same form as sys.version_info: + + (PY_MAJOR_VERSION, # the 2 in 2.1.0a3; an int + PY_MINOR_VERSION, # the 1; an int + PY_MICRO_VERSION, # the 0; an int + PY_RELEASE_LEVEL, # "alpha", "beta", "candidate" or "final"; string + PY_RELEASE_SERIAL # the 3; an int + ) + +OptionalRelease records the first release in which + + from __future__ import FeatureName + +was accepted. + +In the case of MandatoryReleases that have not yet occurred, +MandatoryRelease predicts the release in which the feature will become part +of the language. + +Else MandatoryRelease records when the feature became part of the language; +in releases at or after that, modules no longer need + + from __future__ import FeatureName + +to use the feature in question, but may continue to use such imports. + +MandatoryRelease may also be None, meaning that a planned feature got +dropped. + +Instances of class _Feature have two corresponding methods, +.getOptionalRelease() and .getMandatoryRelease(). + +CompilerFlag is the (bitfield) flag that should be passed in the fourth +argument to the builtin function compile() to enable the feature in +dynamically compiled code. This flag is stored in the .compiler_flag +attribute on _Future instances. These values must match the appropriate +#defines of CO_xxx flags in Include/compile.h. + +No feature line is ever to be deleted from this file. +""" + +all_feature_names = [ + "nested_scopes", + "generators", + "division", + "absolute_import", + "with_statement", + "print_function", + "unicode_literals", +] + +__all__ = ["all_feature_names"] + all_feature_names + +# The CO_xxx symbols are defined here under the same names used by +# compile.h, so that an editor search will find them here. However, +# they're not exported in __all__, because they don't really belong to +# this module. +CO_NESTED = 0x0010 # nested_scopes +CO_GENERATOR_ALLOWED = 0 # generators (obsolete, was 0x1000) +CO_FUTURE_DIVISION = 0x2000 # division +CO_FUTURE_ABSOLUTE_IMPORT = 0x4000 # perform absolute imports by default +CO_FUTURE_WITH_STATEMENT = 0x8000 # with statement +CO_FUTURE_PRINT_FUNCTION = 0x10000 # print function +CO_FUTURE_UNICODE_LITERALS = 0x20000 # unicode string literals + +class _Feature: + def __init__(self, optionalRelease, mandatoryRelease, compiler_flag): + self.optional = optionalRelease + self.mandatory = mandatoryRelease + self.compiler_flag = compiler_flag + + def getOptionalRelease(self): + """Return first release in which this feature was recognized. + + This is a 5-tuple, of the same form as sys.version_info. + """ + + return self.optional + + def getMandatoryRelease(self): + """Return release in which this feature will become mandatory. + + This is a 5-tuple, of the same form as sys.version_info, or, if + the feature was dropped, is None. + """ + + return self.mandatory + + def __repr__(self): + return "_Feature" + repr((self.optional, + self.mandatory, + self.compiler_flag)) + +nested_scopes = _Feature((2, 1, 0, "beta", 1), + (2, 2, 0, "alpha", 0), + CO_NESTED) + +generators = _Feature((2, 2, 0, "alpha", 1), + (2, 3, 0, "final", 0), + CO_GENERATOR_ALLOWED) + +division = _Feature((2, 2, 0, "alpha", 2), + (3, 0, 0, "alpha", 0), + CO_FUTURE_DIVISION) + +absolute_import = _Feature((2, 5, 0, "alpha", 1), + (3, 0, 0, "alpha", 0), + CO_FUTURE_ABSOLUTE_IMPORT) + +with_statement = _Feature((2, 5, 0, "alpha", 1), + (2, 6, 0, "alpha", 0), + CO_FUTURE_WITH_STATEMENT) + +print_function = _Feature((2, 6, 0, "alpha", 2), + (3, 0, 0, "alpha", 0), + CO_FUTURE_PRINT_FUNCTION) + +unicode_literals = _Feature((2, 6, 0, "alpha", 2), + (3, 0, 0, "alpha", 0), + CO_FUTURE_UNICODE_LITERALS) |