============================
API Notes for Foundation
============================

Introduction
------------

This document describes where the wrappers for Foundation API are different
from the default straightforward translation of method/function interfaces.

NSAppleEventDescriptor, NSAppleEventManager
-------------------------------------------

These classes are barely supported, interaction with the lowlevel AppleEvent
machinery is not tested at all and probably doens't work.

Use the ScriptingBridge and/or the `appscript library`_ instead of this
class.

.. _`appscript library`: http://appscript.sourceforge.net/

NSCoder
-------

* ``-encodeValuesOfObjCTypes:``: Use the basic encoding methods instead

* ``-decodeValuesOfObjCTypes:``: Use the basic decodeing methods instead

NSData, NSMutableData
---------------------

* ``-getBytes:``: Use ``-bytes`` instead.

* ``+dataWithBytesNoCopy:length:``, ``-initWithBytesNoCopy:length``: Don't use these, Cocoa
   will try to use the C function ``free()`` on the buffer when the data object is released and
   that won't work.

* ``+dataWithBytesNoCopy:length:freeWhenDone:``, ``-initWithBytesNoCopy:length:freeWhenDone:``: 
  Using these is fairly dangerous, your program can crash when the data buffer is cleaned up by 
  the Python garbage collector before the ``NSData`` object is deallocated. 

  The ``freeWhenDone`` argument must be ``False``.

  Use ``buffer(value)`` instead, those will automaticly be bridged to an instance of a 
  ``NSData`` subclass.

NSDebug
-------

* ``NSDebugEnabled``, ``NSZombieEnabled``, ``NSDeallocateZombies``,
  ``NSHangOnUncaughtException``, ``NSKeepAllocationStatistics``: These values are not available 
  from Python.

* ``NSIsFreedObject``, ``NSFrameAddress``, ``NSReturnAddress``, ``NSCountFrames``:
   These functions are not available from Python.

NSGarbageCollector
------------------

PyObjC does not fully support running with the garbage collector enabled at the moment. 

* ``disableCollectorForPointer:``, ``enableCollectorForPointer:``: These API's are not
  supported at all.

NSGeometry
-----------

* ``NSZeroPoint``, ``NSZeroSize``, ``NSZeroRect``: these are mutable. Do not use them
  to initialize a variable that you'll modify later on, use the default contructor instead.

  This is, instead of::

     point = NSZeroPoint
     # ...
     point.x = 4

  Use::

     point = NPoint()
     # ...
     point.x = 4

  (or even: ``point = NSPoint(x=4)``).

* The CoreGraphics types ``CGPoint``, ``CGSize`` and ``CGRect`` are interchangeable with
  their Foundation counterparts, there is no need to explicitly convert between them.

NSInvocation
------------

* Struct ``NSObjCValue`` and related constants (such as ``NSObjCNoType``) are not available in
  Python.

NSMapTable
----------

* Using ``NSMapTableObjectPointerPersonality`` is not supported. Trying to access values in
  a maptable with this personality for the keys or values will crash your program.

Generic Macros
--------------

* The function/macros ``MIN``, ``MAX`` and ``ABS`` are not available in Python. Use the
  regular python functions ``min``, ``max`` and ``abs`` instead.

NSPointerArray
--------------

This class is only useable when the array is configured for Object use.

NSPointerFunctions
------------------

Accessing the actual function properties (such as ``hashFunction``) is not supported.

NSMachPort delegate
-------------------

Implementing or calling ``handleMachMessage:`` is not supported. The argument is mapped on
a plain python integer, accessing the actual Mach message buffer is not possible.
