Little quiz

[Kai Meyer]

On 03/24/2011 06:50 PM, bearophile wrote:
> A little quiz for people here: guess the output of this little D2 program (it compiles correctly and doesn't crash at run time, so it's a fair question):
>
>
> import std.typecons: tuple;
> import std.c.stdio: printf;
>
> auto foo() {
>      printf("foo\n");
>      return tuple(1, 2);
> }
>
> void main() {
>      foreach (x; foo().tupleof)
>          printf("%d\n", x);
> }
>
>
> Bye,
> bearophile

That's pretty cool :) Seems like we should be able to expect the same 
behavior in all of these, but that doesn't appear to be the case at all.



import std.typecons: tuple;
import std.c.stdio: printf;

auto foo() {
     printf("foo\n");
     return tuple(1, 2);
}

void main() {
     printf("-----\n");
     foreach (x; foo().tupleof)
         printf("%d\n", x);
     printf("-----\n");
     auto f = foo();
     printf("-----\n");
     foreach (x; f.tupleof)
         printf("%d\n", x);
     printf("-----\n");
     auto f2 = foo().tupleof;
     printf("-----\n");
     foreach (x; f2)
         printf("%d\n", x);
     printf("-----\n");
}