Eric Snow's implementation of PEP 421.

warsaw · warsaw · commit 409da157d7ff · 2012-06-03T16:18:47.000-04:00
Issue 14673: Add sys.implementation
diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
@@ -616,6 +616,44 @@ always available.
 
    Thus ``2.1.0a3`` is hexversion ``0x020100a3``.
 
+
+.. data:: implementation
+
+   An object containing the information about the implementation of the
+   currently running Python interpreter.  Its attributes are the those
+   that all Python implementations must implement.  They are described
+   below.
+
+   *name* is the implementation's identifier, like ``'cpython'``.
+
+   *version* is a named tuple, in the same format as
+   :data:`sys.version_info`.  It represents the version of the Python
+   *implementation*.  This has a distinct meaning from the specific
+   version of the Python *language* to which the currently running
+   interpreter conforms, which ``sys.version_info`` represents.  For
+   example, for PyPy 1.8 ``sys.implementation.version`` might be
+   ``sys.version_info(1, 8, 0, 'final', 0)``, whereas ``sys.version_info``
+   would be ``sys.version_info(1, 8, 0, 'final', 0)``.  For CPython they
+   are the same value, since it is the reference implementation.
+
+   *hexversion* is the implementation version in hexadecimal format, like
+   :data:`sys.hexversion`.
+
+   *cache_tag* is the tag used by the import machinery in the filenames of
+   cached modules.  By convention, it would be a composite of the
+   implementation's name and version, like ``'cpython-33'``.  However, a
+   Python implementation may use some other value if appropriate.  If
+   ``cache_tag`` is set to ``None``, it indicates that module caching should
+   be disabled.
+
+   Regardless of its contents, :data:`sys.implementation` will not
+   change during a run of the interpreter, nor between implementation
+   versions.  (It may change between Python language versions,
+   however.)  See `PEP 421` for more information.
+
+   .. versionadded:: 3.3
+
+
 .. data:: int_info
 
    A :term:`struct sequence` that holds information about Python's internal
diff --git a/Doc/library/types.rst b/Doc/library/types.rst
@@ -194,3 +194,27 @@ Standard names are defined for the following types:
       Return a new view of the underlying mapping's values.
 
 
+.. class:: SimpleNamespace
+
+   A simple :class:`object` subclass that provides attribute access to its
+   namespace, as well as a meaningful repr.
+
+   Unlike :class:`object`, with ``SimpleNamespace`` you can add and remove
+   attributes.  If a ``SimpleNamespace`` object is initialized with keyword
+   arguments, those are directly added to the underlying namespace.
+
+   The type is roughly equivalent to the following code::
+
+       class SimpleNamespace:
+           def __init__(self, **kwargs):
+               self.__dict__.update(kwargs)
+           def __repr__(self):
+               keys = sorted(self.__dict__)
+               items = ("{}={!r}".format(k, self.__dict__[k]) for k in keys)
+               return "{}({})".format(type(self).__name__, ", ".join(items))
+
+   ``SimpleNamespace`` may be useful as a replacement for ``class NS: pass``.
+   However, for a structured record type use :func:`~collections.namedtuple`
+   instead.
+
+   .. versionadded:: 3.3
diff --git a/Include/Python.h b/Include/Python.h
@@ -101,6 +101,7 @@
 #include "warnings.h"
 #include "weakrefobject.h"
 #include "structseq.h"
+#include "namespaceobject.h"
 
 #include "codecs.h"
 #include "pyerrors.h"
diff --git a/Include/namespaceobject.h b/Include/namespaceobject.h
@@ -0,0 +1,17 @@
+
+/* simple namespace object interface */
+
+#ifndef NAMESPACEOBJECT_H
+#define NAMESPACEOBJECT_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+PyAPI_DATA(PyTypeObject) _PyNamespace_Type;
+
+PyAPI_FUNC(PyObject *) _PyNamespace_New(PyObject *kwds);
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* !NAMESPACEOBJECT_H */
diff --git a/Lib/test/test_sys.py b/Lib/test/test_sys.py
@@ -581,6 +581,24 @@ def test_getfilesystemencoding(self):
             expected = None
         self.check_fsencoding(fs_encoding, expected)
 
+    def test_implementation(self):
+        # This test applies to all implementations equally.
+
+        levels = {'alpha': 0xA, 'beta': 0xB, 'candidate': 0xC, 'release': 0xF}
+
+        self.assertTrue(hasattr(sys.implementation, 'name'))
+        self.assertTrue(hasattr(sys.implementation, 'version'))
+        self.assertTrue(hasattr(sys.implementation, 'hexversion'))
+        self.assertTrue(hasattr(sys.implementation, 'cache_tag'))
+
+        version = sys.implementation.version
+        self.assertEqual(version[:2], (version.major, version.minor))
+
+        hexversion = (version.major << 24 | version.minor << 16 |
+                      version.micro << 8 | levels[version.releaselevel] << 4 |
+                      version.serial << 0)
+        self.assertEqual(sys.implementation.hexversion, hexversion)
+
 
 class SizeofTest(unittest.TestCase):
 
diff --git a/Lib/test/test_types.py b/Lib/test/test_types.py
@@ -996,8 +996,149 @@ def __prepare__(mcls, name, bases):
             X = types.new_class("X", (int(), C))
 
 
+class SimpleNamespaceTests(unittest.TestCase):
+
+    def test_constructor(self):
+        ns1 = types.SimpleNamespace()
+        ns2 = types.SimpleNamespace(x=1, y=2)
+        ns3 = types.SimpleNamespace(**dict(x=1, y=2))
+
+        with self.assertRaises(TypeError):
+            types.SimpleNamespace(1, 2, 3)
+
+        self.assertEqual(len(ns1.__dict__), 0)
+        self.assertEqual(vars(ns1), {})
+        self.assertEqual(len(ns2.__dict__), 2)
+        self.assertEqual(vars(ns2), {'y': 2, 'x': 1})
+        self.assertEqual(len(ns3.__dict__), 2)
+        self.assertEqual(vars(ns3), {'y': 2, 'x': 1})
+
+    def test_unbound(self):
+        ns1 = vars(types.SimpleNamespace())
+        ns2 = vars(types.SimpleNamespace(x=1, y=2))
+
+        self.assertEqual(ns1, {})
+        self.assertEqual(ns2, {'y': 2, 'x': 1})
+
+    def test_underlying_dict(self):
+        ns1 = types.SimpleNamespace()
+        ns2 = types.SimpleNamespace(x=1, y=2)
+        ns3 = types.SimpleNamespace(a=True, b=False)
+        mapping = ns3.__dict__
+        del ns3
+
+        self.assertEqual(ns1.__dict__, {})
+        self.assertEqual(ns2.__dict__, {'y': 2, 'x': 1})
+        self.assertEqual(mapping, dict(a=True, b=False))
+
+    def test_attrget(self):
+        ns = types.SimpleNamespace(x=1, y=2, w=3)
+
+        self.assertEqual(ns.x, 1)
+        self.assertEqual(ns.y, 2)
+        self.assertEqual(ns.w, 3)
+        with self.assertRaises(AttributeError):
+            ns.z
+
+    def test_attrset(self):
+        ns1 = types.SimpleNamespace()
+        ns2 = types.SimpleNamespace(x=1, y=2, w=3)
+        ns1.a = 'spam'
+        ns1.b = 'ham'
+        ns2.z = 4
+        ns2.theta = None
+
+        self.assertEqual(ns1.__dict__, dict(a='spam', b='ham'))
+        self.assertEqual(ns2.__dict__, dict(x=1, y=2, w=3, z=4, theta=None))
+
+    def test_attrdel(self):
+        ns1 = types.SimpleNamespace()
+        ns2 = types.SimpleNamespace(x=1, y=2, w=3)
+
+        with self.assertRaises(AttributeError):
+            del ns1.spam
+        with self.assertRaises(AttributeError):
+            del ns2.spam
+
+        del ns2.y
+        self.assertEqual(vars(ns2), dict(w=3, x=1))
+        ns2.y = 'spam'
+        self.assertEqual(vars(ns2), dict(w=3, x=1, y='spam'))
+        del ns2.y
+        self.assertEqual(vars(ns2), dict(w=3, x=1))
+
+        ns1.spam = 5
+        self.assertEqual(vars(ns1), dict(spam=5))
+        del ns1.spam
+        self.assertEqual(vars(ns1), {})
+
+    def test_repr(self):
+        ns1 = types.SimpleNamespace(x=1, y=2, w=3)
+        ns2 = types.SimpleNamespace()
+        ns2.x = "spam"
+        ns2._y = 5
+
+        self.assertEqual(repr(ns1), "namespace(w=3, x=1, y=2)")
+        self.assertEqual(repr(ns2), "namespace(_y=5, x='spam')")
+
+    def test_nested(self):
+        ns1 = types.SimpleNamespace(a=1, b=2)
+        ns2 = types.SimpleNamespace()
+        ns3 = types.SimpleNamespace(x=ns1)
+        ns2.spam = ns1
+        ns2.ham = '?'
+        ns2.spam = ns3
+
+        self.assertEqual(vars(ns1), dict(a=1, b=2))
+        self.assertEqual(vars(ns2), dict(spam=ns3, ham='?'))
+        self.assertEqual(ns2.spam, ns3)
+        self.assertEqual(vars(ns3), dict(x=ns1))
+        self.assertEqual(ns3.x.a, 1)
+
+    def test_recursive(self):
+        ns1 = types.SimpleNamespace(c='cookie')
+        ns2 = types.SimpleNamespace()
+        ns3 = types.SimpleNamespace(x=1)
+        ns1.spam = ns1
+        ns2.spam = ns3
+        ns3.spam = ns2
+
+        self.assertEqual(ns1.spam, ns1)
+        self.assertEqual(ns1.spam.spam, ns1)
+        self.assertEqual(ns1.spam.spam, ns1.spam)
+        self.assertEqual(ns2.spam, ns3)
+        self.assertEqual(ns3.spam, ns2)
+        self.assertEqual(ns2.spam.spam, ns2)
+
+    def test_recursive_repr(self):
+        ns1 = types.SimpleNamespace(c='cookie')
+        ns2 = types.SimpleNamespace()
+        ns3 = types.SimpleNamespace(x=1)
+        ns1.spam = ns1
+        ns2.spam = ns3
+        ns3.spam = ns2
+
+        self.assertEqual(repr(ns1),
+                         "namespace(c='cookie', spam=namespace(...))")
+        self.assertEqual(repr(ns2),
+                         "namespace(spam=namespace(spam=namespace(...), x=1))")
+
+    def test_as_dict(self):
+        ns = types.SimpleNamespace(spam='spamspamspam')
+
+        with self.assertRaises(TypeError):
+            len(ns)
+        with self.assertRaises(TypeError):
+            iter(ns)
+        with self.assertRaises(TypeError):
+            'spam' in ns
+        with self.assertRaises(TypeError):
+            ns['spam']
+
+
 def test_main():
-    run_unittest(TypesTests, MappingProxyTests, ClassCreationTests)
+    run_unittest(TypesTests, MappingProxyTests, ClassCreationTests,
+                 SimpleNamespaceTests)
 
 if __name__ == '__main__':
     test_main()
diff --git a/Lib/types.py b/Lib/types.py
@@ -13,6 +13,7 @@ def _f(): pass
 LambdaType = type(lambda: None)         # Same as FunctionType
 CodeType = type(_f.__code__)
 MappingProxyType = type(type.__dict__)
+SimpleNamespace = type(sys.implementation)
 
 def _g():
     yield 1
diff --git a/Makefile.pre.in b/Makefile.pre.in
@@ -392,6 +392,7 @@ OBJECT_OBJS=	\
 		Objects/memoryobject.o \
 		Objects/methodobject.o \
 		Objects/moduleobject.o \
+		Objects/namespaceobject.o \
 		Objects/object.o \
 		Objects/obmalloc.o \
 		Objects/capsule.o \
@@ -766,6 +767,7 @@ PYTHON_HEADERS= \
 		$(srcdir)/Include/methodobject.h \
 		$(srcdir)/Include/modsupport.h \
 		$(srcdir)/Include/moduleobject.h \
+		$(srcdir)/Include/namespaceobject.h \
 		$(srcdir)/Include/node.h \
 		$(srcdir)/Include/object.h \
 		$(srcdir)/Include/objimpl.h \
diff --git a/Objects/namespaceobject.c b/Objects/namespaceobject.c
diff --git a/Objects/object.c b/Objects/object.c
diff --git a/Python/sysmodule.c b/Python/sysmodule.c
