types: Add pristine from Python-3.3.3 tarball.

Author: pfalcon

types/types.py

@@ -0,0 +1,101 @@
+"""
+Define names for built-in types that aren't directly accessible as a builtin.
+"""
+import sys
+
+# Iterators in Python aren't a matter of type but of protocol.  A large
+# and changing number of builtin types implement *some* flavor of
+# iterator.  Don't check the type!  Use hasattr to check for both
+# "__iter__" and "__next__" attributes instead.
+
+def _f(): pass
+FunctionType = type(_f)
+LambdaType = type(lambda: None)         # Same as FunctionType
+CodeType = type(_f.__code__)
+MappingProxyType = type(type.__dict__)
+SimpleNamespace = type(sys.implementation)
+
+def _g():
+    yield 1
+GeneratorType = type(_g())
+
+class _C:
+    def _m(self): pass
+MethodType = type(_C()._m)
+
+BuiltinFunctionType = type(len)
+BuiltinMethodType = type([].append)     # Same as BuiltinFunctionType
+
+ModuleType = type(sys)
+
+try:
+    raise TypeError
+except TypeError:
+    tb = sys.exc_info()[2]
+    TracebackType = type(tb)
+    FrameType = type(tb.tb_frame)
+    tb = None; del tb
+
+# For Jython, the following two types are identical
+GetSetDescriptorType = type(FunctionType.__code__)
+MemberDescriptorType = type(FunctionType.__globals__)
+
+del sys, _f, _g, _C,                              # Not for export
+
+
+# Provide a PEP 3115 compliant mechanism for class creation
+def new_class(name, bases=(), kwds=None, exec_body=None):
+    """Create a class object dynamically using the appropriate metaclass."""
+    meta, ns, kwds = prepare_class(name, bases, kwds)
+    if exec_body is not None:
+        exec_body(ns)
+    return meta(name, bases, ns, **kwds)
+
+def prepare_class(name, bases=(), kwds=None):
+    """Call the __prepare__ method of the appropriate metaclass.
+
+    Returns (metaclass, namespace, kwds) as a 3-tuple
+
+    *metaclass* is the appropriate metaclass
+    *namespace* is the prepared class namespace
+    *kwds* is an updated copy of the passed in kwds argument with any
+    'metaclass' entry removed. If no kwds argument is passed in, this will
+    be an empty dict.
+    """
+    if kwds is None:
+        kwds = {}
+    else:
+        kwds = dict(kwds) # Don't alter the provided mapping
+    if 'metaclass' in kwds:
+        meta = kwds.pop('metaclass')
+    else:
+        if bases:
+            meta = type(bases[0])
+        else:
+            meta = type
+    if isinstance(meta, type):
+        # when meta is a type, we first determine the most-derived metaclass
+        # instead of invoking the initial candidate directly
+        meta = _calculate_meta(meta, bases)
+    if hasattr(meta, '__prepare__'):
+        ns = meta.__prepare__(name, bases, **kwds)
+    else:
+        ns = {}
+    return meta, ns, kwds
+
+def _calculate_meta(meta, bases):
+    """Calculate the most derived metaclass."""
+    winner = meta
+    for base in bases:
+        base_meta = type(base)
+        if issubclass(winner, base_meta):
+            continue
+        if issubclass(base_meta, winner):
+            winner = base_meta
+            continue
+        # else:
+        raise TypeError("metaclass conflict: "
+                        "the metaclass of a derived class "
+                        "must be a (non-strict) subclass "
+                        "of the metaclasses of all its bases")
+    return winner