On 11/25/05, Thomas Chust <[EMAIL PROTECTED]> wrote:
>
> Building NSInvocation instances is even easier than doing everything by
> hand -- for example the parsing of ObjC parameter type encoding strings
> is much less work, because the NSMethodSignature objects at least split
> them
> correctly for you. You just have to create the object, set the parameters,
> execute the call and retrieve the return value -- like in this pseudocode
> snippet:
> SEL sel = sel_registerName("someSelector");
> NSMethodSignature *sig = [someObject methodSignatureForSelector:sel];
> NSInvocation *inv = [NSInvocation invocationWithMethodSignature:sig];
> [inv setTarget:someObject];
> [inv setSelector:sel];
> for (int i = 2; i < [sig numberOfArguments]; i++)
> [inv setArgument:convertArgumentFromScheme(i-2, [sig
> getArgumentTypeAtIndex:i])
> atIndex:i];
> [inv invoke];
> void *rbuf = alloca([sig methodReturnLength]);
> [inv getReturnValue:rbuf];
> convertReturnValueToScheme([sig methodReturnType], rbuf);
> [inv release];
> [sig release];
Yes, this looks fine. Can one assume the buffer for arguments/return values
uses a "natural" representation?
>
> But I don't want to urge you not to use the library of your choice if you
> find
> it more convenient.
I don't want to force libffi on everybody - it worked for me and simplifies
certain things tremendously. That it's so horribly maintained is definitely
an argument against using it.
cheers,
felix
_______________________________________________
Chicken-users mailing list
[email protected]
http://lists.nongnu.org/mailman/listinfo/chicken-users
