On Sun, 16 Aug 2009 17:43:04 +0100, Luís Oliveira wrote:
On Sun, Aug 16, 2009 at 5:14 PM, Tamas K Papptkpapp@gmail.com wrote:
Is there a way to make mem-aref work with CL's complex numbers? I don't need anything else from CFFI (no complex function arguments, return types, etc), just mem-aref, eg something like
(mem-aref ptr :complex-float 11)
That is doable with something like:
(defmethod translate-from-foreign (ptr (type complex-float-type)) (complex (mem-aref ptr :float 0) (mem-aref ptr :float 1)))
(setf (mem-aref ptr :complex-float 12) #C(1s0 2s0))
But that isn't. Would defining your own setter work for you?
(defun complex-float-aref (ptr index c) (let ((p (* (foreign-type-size :complex-float) index))) (setf (mem-aref p :float 0) (realpart c) (mem-aref p :float 1) (imagpart c))))
To do that with plain MEM-AREF as you wanted, I think we would need some sort of TRANSLATE-INTO-FOREIGN hook.
Thanks for the quick reply. Yes, my own setter works, and I managed to prettify my code by writing a wrapper around mem-aref that calls the setter above when necessary. But if mem-ref and mem-aref could be extended to handle C99 complex types in the future, that would be neat (that means that my code would more more standard, and I would benefit from optimizations like compiler macros, etc).
Tamas