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    "annotations",
61]
62
63__all__ = ["all_feature_names"] + all_feature_names
64
65# The CO_xxx symbols are defined here under the same names defined in
66# code.h and used by compile.h, so that an editor search will find them here.
67# However, they're not exported in __all__, because they don't really belong to
68# this module.
69CO_NESTED            = 0x0010   # nested_scopes
70CO_GENERATOR_ALLOWED = 0        # generators (obsolete, was 0x1000)
71CO_FUTURE_DIVISION   = 0x2000   # division
72CO_FUTURE_ABSOLUTE_IMPORT = 0x4000 # perform absolute imports by default
73CO_FUTURE_WITH_STATEMENT  = 0x8000   # with statement
74CO_FUTURE_PRINT_FUNCTION  = 0x10000   # print function
75CO_FUTURE_UNICODE_LITERALS = 0x20000 # unicode string literals
76CO_FUTURE_BARRY_AS_BDFL = 0x40000
77CO_FUTURE_GENERATOR_STOP  = 0x80000 # StopIteration becomes RuntimeError in generators
78CO_FUTURE_ANNOTATIONS     = 0x100000  # annotations become strings at runtime
79
80class _Feature:
81    def __init__(self, optionalRelease, mandatoryRelease, compiler_flag):
82        self.optional = optionalRelease
83        self.mandatory = mandatoryRelease
84        self.compiler_flag = compiler_flag
85
86    def getOptionalRelease(self):
87        """Return first release in which this feature was recognized.
88
89        This is a 5-tuple, of the same form as sys.version_info.
90        """
91
92        return self.optional
93
94    def getMandatoryRelease(self):
95        """Return release in which this feature will become mandatory.
96
97        This is a 5-tuple, of the same form as sys.version_info, or, if
98        the feature was dropped, is None.
99        """
100
101        return self.mandatory
102
103    def __repr__(self):
104        return "_Feature" + repr((self.optional,
105                                  self.mandatory,
106                                  self.compiler_flag))
107
108nested_scopes = _Feature((2, 1, 0, "beta",  1),
109                         (2, 2, 0, "alpha", 0),
110                         CO_NESTED)
111
112generators = _Feature((2, 2, 0, "alpha", 1),
113                      (2, 3, 0, "final", 0),
114                      CO_GENERATOR_ALLOWED)
115
116division = _Feature((2, 2, 0, "alpha", 2),
117                    (3, 0, 0, "alpha", 0),
118                    CO_FUTURE_DIVISION)
119
120absolute_import = _Feature((2, 5, 0, "alpha", 1),
121                           (3, 0, 0, "alpha", 0),
122                           CO_FUTURE_ABSOLUTE_IMPORT)
123
124with_statement = _Feature((2, 5, 0, "alpha", 1),
125                          (2, 6, 0, "alpha", 0),
126                          CO_FUTURE_WITH_STATEMENT)
127
128print_function = _Feature((2, 6, 0, "alpha", 2),
129                          (3, 0, 0, "alpha", 0),
130                          CO_FUTURE_PRINT_FUNCTION)
131
132unicode_literals = _Feature((2, 6, 0, "alpha", 2),
133                            (3, 0, 0, "alpha", 0),
134                            CO_FUTURE_UNICODE_LITERALS)
135
136barry_as_FLUFL = _Feature((3, 1, 0, "alpha", 2),
137                          (3, 9, 0, "alpha", 0),
138                          CO_FUTURE_BARRY_AS_BDFL)
139
140generator_stop = _Feature((3, 5, 0, "beta", 1),
141                          (3, 7, 0, "alpha", 0),
142                          CO_FUTURE_GENERATOR_STOP)
143
144annotations = _Feature((3, 7, 0, "beta", 1),
145                       (4, 0, 0, "alpha", 0),
146                       CO_FUTURE_ANNOTATIONS)
147