Function calls

[Lars T. Kyllingstad]

bearophile wrote:
> I have written the following closure, to generate numbers in 1-7 from numbers in 1-5, as alternative implementation of this:
> http://rosettacode.org/wiki/Seven-dice_from_Five-dice#D
> 
> auto dice7Gen(alias d5)() {
>     int rem = 0;
>     int max = 1;
> 
>     int gen7() {
>         while (rem / 7 == max / 7) {
>             while (max < 7) {
>                 int rand5 = d5() - 1;
>                 max *= 5;
>                 rem = 5 * rem + rand5;
>             }
> 
>             int groups = max / 7;
>             if (rem >=  7 * groups) {
>                 rem -= 7 * groups;
>                 max -= 7 * groups;
>             }
>         }
> 
>         int result = rem % 7;
>         rem /= 7;
>         max /= 7;
>         return result + 1;
>     }
> 
>     return gen7;
> }
> 
> Can you spot the bug? It returns an integer instead of a closure :-)
> The correct last line has to be:
>     return &gen7;
> 
> But I think the real "bug" here is in the D2 design. In D2 calling callables without () has to be disallowed:
> - & to take their reference/address
> - () to call them
> Otherwise syntax error at compile-time.
> 
> Only properties marked with @property are allowed to be called without (). (If you really want it, then even free functions may be allowed to be marked with @property. This probably will not cause many bugs).
> 
> This can avoid bugs and tidy the language a little more.
> 
> Bye,
> bearophile


I thought that this issue had been settled a long time ago, and that 
this was the whole point of @property.

-Lars