Release Notes

1.2

This release provides some important bug fixes, some new features, and a new copyright.

New functionality:

• One or more mapping objects can be passed to the MultiMapping constructor.

• MultiMapping objects implement the has_key and get methods as defined for Python 1.5 dictionaries.

Bugs fixed:

• When support was added for passing acquisition wrappers to methods of data-less C mix-in classes, C-based __call_method__ hooks were broken. The most notable example of this was the breaking of the Synchronized class.

• Calling C-base-class special methods from overriding methods, as in::

            class LowerMultiMapping(MultiMapping):
  
              def __getitem__(self, key):
                return MultiMapping.__getitem__(self, lower(key))
  
          caused infinite loops.
  
  

• A typo in the Acquisition probably caused __delitem__ calls on wrapped mapping objects to fail.

1.1

New functionality:

• Changed the way that methods in pure mix-in classes are constructed. Now methods are wrapped in such a way that tricky wrapper objects (like Acquisition wrappers) can bind them to wrapped objects.

• An "is subclass" test is provided via the macros ExtensionClassSubclass_Check, and ExtensionClassSubclassInstance_Check, which are documented in ExtensionClass.h.

• Methods and Acquisition wrappers use free list to improve allocation and deallocation performance.

• Bound methods have attributes who's values are stored in their instances.

• Added __module__ attribute to ExtensionClasses to be consistent with Python 1.5 classes and to work correctly with 1.5 pickling.

• Added the __basic__ new class method to allow ExtensionClass instances to be unpickled without calling their constructors.

• Acquired acquiring objects can nor acquire from the object they were accessed in, in addition to the object they were acquired from.

• Added new Acquisition variable, Acquired, to support "Controlled Acquisition'.

• Added a new aq_acquire method for objects that subclass Acquisition.Implicit or Acquisition.Explicit. This supports explicit acquisition and provides an option filter function to support "Filtered Acquisiition".

  The acquire method available in earlier releases is still available, but is deprecated.

Bugs fixed:

• There were some incorrect C-level error return values.

• A bug in handling method chains caused "C inheritence" to fail. This only affected extension types that inherited from extension types using method chains, not extension subclasses defined in Python inheriting from extension base classes defined in C.

• Expressions like not foo or statements like::

           if foo:
             ...
  
          often failed for non-collection types because of an
          incorrect attempt to take the 'len' of an object.
  
  

• Comparisons of objects with different classes didn't work correctly.

• Instances provided access to their class __bases__ attribute.

1.0.2

Bugs fixed:

• Fixed bug in handling subclasses of Sequence objects.

• Fixed comparison bug in Missing objects.

1.0.1

Added functionality to and fixed bug in Missing module

• Fixed horible reference-counting bug

• Changed so that Missing.Value.spam(a1,a2,whatever) returns Missing.Value for any method name (except __reduce__) and any arguments.

• Changed so that missing values are picklable. Note that the special global, Missing.Value, is pickled in a slightly more efficient manner than other missing values.

1.0

First non-beta release

This release is the result of a major rewrite and "hardening" effort to increase performance and reliability. This version is being used in several Digital Creations products, so if parts are broken, we probably don't use them. :-)

This release also contains several new features and example modules, including:

• Acquisition,

• Custom method calls,

• Class initialization protocol,

• A class method that makes it possible to explicitly call Python base-class methods.

• A sample application of custom method calls that provides Java-like synchronized classes that prevent more than one thread from accessing an object's methods at one time.

Note that there is one known incompatibility with previous releases. In previouse releases, the method used to support context wrapping was named __bind_to_object__. The name of this method was changed to __of__ in this release and I do not expect this name to change in the future.