How to use map?

[bearophile via Digitalmars-d-learn]

Lemonfiend:

> If I instead do ie. map!`cast(int)a` it works fine.
> What am I missing?

Generally don't use casts, unless you know what you are doing 
(and often you don't).

The code you were trying to write:

struct Foo(T) {
     T t;
}

void main() {
     import std.stdio, std.algorithm, std.array;

     float[] vals = [1.1, 2.1, 3.1, 4.1];
     auto arr = vals.map!(Foo!float).array;
     arr.writeln;
}

Bye,
bearophile