David Robins wrote:
What's the cleanest way to return a new PMC from an op?e.g. Suppose I have a Vec2D_in_X_plane and a Vec2D_in_Y_plane and I add them and want to always produce a Vec3D - is this correct (and is it efficient?): void add(PMC* value, PMC* dest) { if(value->vtable == &Parrot_base_vtables[enum_class_Vec2D_in_Y_plane]) {
always compare ids (vtables may change) - yes, many pmc's do like above, but will need changes too.
PMC* ret = pmc_new(INTERP,enum_class_Vec3D);
morph "dest" to be a "ret"? unimplemented, unused, but your examples seems to be a typical test case.
if(dest->flags & PMC_active_destroy_FLAG)
dest->vtable->destroy(interpreter,dest);
Just forget "dest", it will be collected when unused.
*dest = *ret;
Brr, will break for sure somewhere. PMCs might even be of different size - Not now, but who knows)
(Arising from this is: how do I check the type of an extension PMC?
All pretty much uncertain in distant fog for me.
Dave
leo
