[fpc-devel] Function variables and overload

[Peter Vreman]

> Hello,
>
> Let's say there is a function
>
>   function ICmp(A,B: PBigInt): SInt32;
>
> and a TBigIntList class having the following method that can
> sort the list according to Cmp
>
>   procedure TBigIntList.Sort(Cmp: TBigIntCompareFunc);
>
> with, of course,
>
>   type TBigIntCompareFunc = function(A,B: PBigInt): SInt32;
>
>
> Now, if ICmp is not overloaded, there is no problem, the call
>
>   L.Sort(@ICmp);
>
> works. But, of course, it doesn't work if ICmp is overloaded.
> In fact, we cannot have both overloaded functions _and_ the
> the possibility to use them as variables. Yes, there are
> ways to fix the problem (no overload or embedding the
> overloaded functions in local functions) but none is really
> satisfying.
>
> Would it be possible to get something like
>
>   L.Sort(@ICmp(PBigInt,PBigInt));
>
> in case ICmp is overloaded? If we could add the parameter
> types, there would be no more ambiguity, the compiler would

There is ambiguity with a normal call to the function. The compiler sees
the ( and thinks it is parsing a call to Icmp().