On Sun, Apr 20, 2008 at 12:17 AM, Andy Lester <[EMAIL PROTECTED]> wrote:
> Just popping in to say that we cannot const any parms to vtable methods. > Parrot can't impose promises on the called code. So take for example In default.pmc the method get_class: VTABLE PMC *get_class() :const That is expanded in default.c as: PMC * Parrot_default_get_class(PARROT_INTERP, const PMC *pmc) And inside this function: INTVAL type = VTABLE_type(interp, pmc); And VTABLE_type is: #define VTABLE_type(interp, pmc) \ (pmc)->vtable->type(interp, pmc) The type of the 'type' function is: typedef INTVAL (*type_method_t)(PARROT_INTERP, PMC* pmc); pmc points to non const PMC. So we have a problem. If vtable method params can't be const, a const method can't call any vtable function without a cast removing constnes, as long as the :const attribute is mapped in C to a const in SELF. So it looks like if vtable methods can't be const, then pmc methods can't be const at the C level without a nightmare of casts adding and removing constness. -- Salu2
