1"""Record of phased-in incompatible language changes.
2
3Each line is of the form:
4
5    FeatureName = "_Feature(" OptionalRelease "," MandatoryRelease ","
6                              CompilerFlag ")"
7
8where, normally, OptionalRelease < MandatoryRelease, and both are 5-tuples
9of 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
18OptionalRelease records the first release in which
19
20    from __future__ import FeatureName
21
22was accepted.
23
24In the case of MandatoryReleases that have not yet occurred,
25MandatoryRelease predicts the release in which the feature will become part
26of the language.
27
28Else MandatoryRelease records when the feature became part of the language;
29in releases at or after that, modules no longer need
30
31    from __future__ import FeatureName
32
33to use the feature in question, but may continue to use such imports.
34
35MandatoryRelease may also be None, meaning that a planned feature got
36dropped.
37
38Instances of class _Feature have two corresponding methods,
39.getOptionalRelease() and .getMandatoryRelease().
40
41CompilerFlag is the (bitfield) flag that should be passed in the fourth
42argument to the builtin function compile() to enable the feature in
43dynamically compiled code.  This flag is stored in the .compiler_flag
44attribute on _Future instances.  These values must match the appropriate
45#defines of CO_xxx flags in Include/compile.h.
46
47No feature line is ever to be deleted from this file.
48"""
49
50all_feature_names = [
51    "nested_scopes",
52    "generators",
53    "division",
54    "absolute_import",
55    "with_statement",
56    "print_function",
57    "unicode_literals",
58    "barry_as_FLUFL",
59    "generator_stop",
60]
61
62__all__ = ["all_feature_names"] + all_feature_names
63
64# The CO_xxx symbols are defined here under the same names used by
65# compile.h, so that an editor search will find them here.  However,
66# they're not exported in __all__, because they don't really belong to
67# this module.
68CO_NESTED            = 0x0010   # nested_scopes
69CO_GENERATOR_ALLOWED = 0        # generators (obsolete, was 0x1000)
70CO_FUTURE_DIVISION   = 0x2000   # division
71CO_FUTURE_ABSOLUTE_IMPORT = 0x4000 # perform absolute imports by default
72CO_FUTURE_WITH_STATEMENT  = 0x8000   # with statement
73CO_FUTURE_PRINT_FUNCTION  = 0x10000   # print function
74CO_FUTURE_UNICODE_LITERALS = 0x20000 # unicode string literals
75CO_FUTURE_BARRY_AS_BDFL = 0x40000
76CO_FUTURE_GENERATOR_STOP  = 0x80000 # StopIteration becomes RuntimeError in generators
77
78class _Feature:
79    def __init__(self, optionalRelease, mandatoryRelease, compiler_flag):
80        self.optional = optionalRelease
81        self.mandatory = mandatoryRelease
82        self.compiler_flag = compiler_flag
83
84    def getOptionalRelease(self):
85        """Return first release in which this feature was recognized.
86
87        This is a 5-tuple, of the same form as sys.version_info.
88        """
89
90        return self.optional
91
92    def getMandatoryRelease(self):
93        """Return release in which this feature will become mandatory.
94
95        This is a 5-tuple, of the same form as sys.version_info, or, if
96        the feature was dropped, is None.
97        """
98
99        return self.mandatory
100
101    def __repr__(self):
102        return "_Feature" + repr((self.optional,
103                                  self.mandatory,
104                                  self.compiler_flag))
105
106nested_scopes = _Feature((2, 1, 0, "beta",  1),
107                         (2, 2, 0, "alpha", 0),
108                         CO_NESTED)
109
110generators = _Feature((2, 2, 0, "alpha", 1),
111                      (2, 3, 0, "final", 0),
112                      CO_GENERATOR_ALLOWED)
113
114division = _Feature((2, 2, 0, "alpha", 2),
115                    (3, 0, 0, "alpha", 0),
116                    CO_FUTURE_DIVISION)
117
118absolute_import = _Feature((2, 5, 0, "alpha", 1),
119                           (3, 0, 0, "alpha", 0),
120                           CO_FUTURE_ABSOLUTE_IMPORT)
121
122with_statement = _Feature((2, 5, 0, "alpha", 1),
123                          (2, 6, 0, "alpha", 0),
124                          CO_FUTURE_WITH_STATEMENT)
125
126print_function = _Feature((2, 6, 0, "alpha", 2),
127                          (3, 0, 0, "alpha", 0),
128                          CO_FUTURE_PRINT_FUNCTION)
129
130unicode_literals = _Feature((2, 6, 0, "alpha", 2),
131                            (3, 0, 0, "alpha", 0),
132                            CO_FUTURE_UNICODE_LITERALS)
133
134barry_as_FLUFL = _Feature((3, 1, 0, "alpha", 2),
135                         (3, 9, 0, "alpha", 0),
136                         CO_FUTURE_BARRY_AS_BDFL)
137
138generator_stop = _Feature((3, 5, 0, "beta", 1),
139                         (3, 7, 0, "alpha", 0),
140                         CO_FUTURE_GENERATOR_STOP)
141