[Bf-python] tp_getset update

[Ken Hughes]

Back from about 6 days on train riding across the US.  I read through 
all the BPy source files and noted what getStuff()/setStuff() methods 
did not have corresponding attributes or used different arguments from 
existing attributes.  As of last last week I started implementing some 
of the changes (which I'll upload to the patch tracker shortly) and (of 
course) would appreciate feedback upon ASAP before continuing with other 
modules (two of the most pressing implementation issues are mentioned 
below).  I also made some notes on inconsistencies in the API 
implementation which, once I organize, I'll put on the wiki.

Some issues with the conversion so far:
     (1) approximately 85% of the setters are "boilerplate", simply 
taking either an integer or float, range-checking or clamping the value, 
then assigning to an element in a structure.  So I've implemented some 
helper EXPP_* procedures (in gen_utils.c) which do much of the work. 
For example:

static int Material_setHardness( BPy_Material * self, PyObject * value )
{
     return EXPP_setShortClamped ( value, &self->material->har,
                                 EXPP_MAT_HARD_MIN,
                                 EXPP_MAT_HARD_MAX );
}

static int Lamp_setType( BPy_Lamp * self, PyObject * value )
{
     return EXPP_setShortRange ( value, &self->lamp->type,
                                 0, EXPP_LAMP_TYPE_MAX );
}

     (2) approximately 90% of the setStuff() methods are also 
"boilerplate"; for these, I'm implementing a *_setterWrapper() procedure:

static PyObject *X_setterWrapper ( BPy_X * self, PyObject * args,
                   int (*func)( BPy_X * self, PyObject * args ));

which check the arg type, retrieves it using PySequence_Get_Item() and 
passes to the setter function (*func), then returns either Py_None or 
NULL (for an exception).  This makes the new setStuff() procedures very
simple (for example):

static PyObject *Camera_oldsetScale(BPy_Camera * self, PyObject * args)
{
     return Camera_setterWrapper ( self, args, Camera_setScale );
}

     (3) does anyone have an idea how the doc field in the tp_getset is
accessed?  For example:

          {"bias",
          (getter)Lamp_getBias, (setter)Lamp_setBias,
          "Lamp shadow map sampling bias",
          NULL},

If I try "print lamp.bias.__doc__" I get a doc string explaining how to 
use a float (which is the type of "bias").  I haven't found anything in 
the Python docs which explain how to access this field; maybe it isn't 
implemented yet?

Ken