On Mon, 19 Apr 2010 00:12:28 +0000 (UTC), Graham Fawcett
<fawc...@uwindsor.ca> wrote:
>
> Hi folks,
>
> I'd like to wrap a family of C functions that look like this:
>
> gboolean fooXXX(arg1, ..., argN, GError** err)
>
> Their signatures and arities vary, but they all have a GError** as
> their last argument. If a function returns false, then 'err' will be
> set to a relevant Error struct.
>
> I would like to write a wrapper that would let me call these functions
> sort of like this:
>
> check!(fooXXX(arg1, ..., argN))
>
> where the 'check' expression would be equivalent to:
>
> GError* err;
> bool ok = fooXXX(arg1, ..., argN, &err);
> if (!ok)
> throw new Exception((*err).message);
>
> Does D (2.0) offer a metaprogramming technique I could use to
> accomplish this -- particularly, to inject that 'err' argument into
> the tail of the fooXXX call?
>
> Thanks,
> Graham
You can use some expression tuple magic to accomplish something like
that:
bool check(alias func, EL ...)() {
GError* err;
bool ok = func(EL, &err);
if (!ok)
throw new Exception((*err).message);
return ok;
}
// used like:
check!(fooXXX, arg1, ..., argN);
See http://digitalmars.com/d/2.0/template.html#TemplateTupleParameter
