API Notes: JavaScriptCore framework
===================================

API Level
---------

The JavaScriptCore library is very low-level and the Python bindings don't change that. This means interacting with JavaScript
through these bindings require a fairly large amount of code.

A future version of these bindings might grow a simpler to use convenience API, but that is unlikely to happen soon because
I have no pressing need for such an API. Contributions that make the JavaScriptCore APIs easier to use would be greatly appreciated.


Reference counting
------------------

The various JavaScriptCore types (such as ``JSValueRef`` and ``JSContextRef``) are C types with manual reference counting. PyObjC
does *not* manage the reference counts for you, you'll have to call the correct retain and release functions manually to avoid
leaking memory and/or crashing.


``autoreleasing``
-----------------

This is a context manager that makes it easier to deal with reference counts::

    with JavaScriptCore.autoreleasing(expression) as value:
       pass

is more or less equivalant to::

     value = expression
     try:
          pass

     finally:
          JavaScriptCore.JSReleaseContext(value)

The actual release function used depends on the type of *value*.



``JSStringGetCharactersPtr``
----------------------------

This function is not supported. Convert the string to a Python type using ``JSStringCopyCFString`` or ``JSStringGetUTF8CString``.

``JSObjectMake``, ``JSObjectGetPrivate``, ``JSObjectSetPrivate``
----------------------------------------------------------------

The private data of an object is a ``void*`` in (Objective-)C, and an integer in Python. Use the ``objc.context`` object to attach
arbitrary data to an object::

   anObj = ... #
   JavaScriptCore.JSOObjectSetPrivate(anObject, objc.context.register(aValue))
   aValue = objc.context.get(JavaScriptCore.JSObjectGetPrivate(anObject))


``JSClassCreate``, ``kJSClassDefinitionEmpty``
----------------------------------------------

Not supported at the moment as this requires manual wrappers (C code).
