[Pyrex] Please support C++

[Lenard Lindstrom]

On 18 Oct 2005 at 8:53, David M. Cooke wrote:

> On Oct 17, 2005, at 18:04, David M. Cooke wrote:
> > Oooh, this sounds like what I was trying figure out, to track down
> > some more compiler warnings. Basically, (PyObject *) was being used to
> > cast an extension type, even when there was an explicit cast to  
> > that type.
> > I'm currently getting around it with a postprocessor on the generated
> > .c file.
> 
> Greg asked me to post an example:
> 
[Pyrex code snip]
> 
> def donothing(o):
>      cdef ArrayType array1, array2
> 
>      array1 = PyArray_ContiguousFromObject(o, PyArray_DOUBLE, 1, 1)
>      array2 = <ArrayType>PyArray_ContiguousFromObject(o,  
> PyArray_DOUBLE, 1, 1)
> 
Thanks. This gave me problems too. But it was quickly fixed with the assignment 
casting system I added to Pyrex. 

> The two calls to PyArray_ContiguousFromObject generate code that set  
> array1 and array2 like this:
> 
[C code snip]
> 
>    /* "/home/cookedm/stuff/python/Numeric/pyrex-api/testcast.pyx":32 */
>    __pyx_1 = ((PyObject *)PyArray_ContiguousFromObject 
> (__pyx_v_o,PyArray_DOUBLE,1
> ,1)); if (!__pyx_1) {__pyx_filename = __pyx_f[0]; __pyx_lineno = 32;  
> goto __pyx_
> L1;}
>    Py_INCREF(((PyObject *)__pyx_1));
>    Py_DECREF(((PyObject *)__pyx_v_array2));
>    __pyx_v_array2 = ((PyObject *)__pyx_1);
>    Py_DECREF(__pyx_1); __pyx_1 = 0;
> 

    /* "C:\user\projects\python23\pyrex_test\array\assign.pyx":33 */
    __pyx_1 = ((PyObject *)PyArray_ContiguousFromObject(__pyx_v_o,PyArray_DOUBLE,1,1)); if (!__pyx_1) {__pyx_filename = __pyx_f[0]; __pyx_lineno = 33; goto __pyx_L1;}
    Py_INCREF(((PyObject *)__pyx_1));
    Py_DECREF(((PyObject *)__pyx_v_array2));
    __pyx_v_array2 = (PyArrayObject *)((PyObject *)__pyx_1);
    Py_DECREF(__pyx_1); __pyx_1 = 0;

Is this better? The example compiled as VC++ 6.0 without a peep. It is not pretty, 
but it works. This is what you get when you have casts that aren't quiet casts. I have 
retained automatic conversion of extension types to (PyObject *). But if it is 
removed the assignment casting system will accommodate the change.

P.S.

I have the patch to remove some the warnings due to unreferenced variables but 
have to tried it since I do not know how it will interact with my changes. I will like to 
try it when I am finished with this.

Lenard Lindstrom
<len-l at telus.net>