Is there an elegant way of making a Result eager instead of lazy?

[ixid]

I understand the point of lazy evaluation but I often want to use 
the lazy algorithm library functions in an eager way. Other than 
looping through them all which feels rather messy is there a good 
way of doing this?

Is there a reason not to allow the following to be automatically 
treated eagerly or is there some kind of cast or conv way of 
doing it?

        int[] test1 = [1,2,3,4];
        int[] test2 = map!("a + a")(test1); //Eager, not allowed

        auto test3 = map!("a + a")(test1); //Lazy