[fpc-devel] Unicode and UTF8String

[Jonas Maebe]

On 01 Dec 2008, at 22:33, Martin Friebe wrote:

> I suggested to have a rtl, that has overloaded functions for each  
> string type.
> of course that sounds easier than in fact it will be.
>
> Florian pointed out a few issues, like overloading by result is not  
> possible (yet?).

No, it is fundamentally impossible. First of all, because a Pascal  
compiler does not look at how the result of an expression is used  
while parsing the expression (so while evaluating a function call, the  
compiler has no idea what the "expected" result type is). That's  
simply how Pascal works.

And how could the compiler decide what to call here:

function f: longint;
begin
   result:=1;
end;

function f: string;
begin
   result:='s';
end;

begin
   writeln(f);
end.

There are an immense amount of similar examples possible (and if you  
add operator overloading in the mix, it increases exponentially), and  
you'd get a huge amount of "can't decide which overloaded function to  
call" errors even if the compiler were hacked to take the use of the  
function results into account.


Jonas