import std.stdio, std.algorithm;

​

void main(string[] args)

{

    {

        enum foo = "a + 0.5 * b";

        auto r = [0, 1, 2, 3];

        auto r1 = reduce!foo(r); //<-- HERE

        auto r2 = reduce!(foo, foo,)(r);

        writeln(r1);

        writeln(r2);

    }

​

    {

        const(char)[] foo(const(char)[] a, const(char)[] b) { return a ~ b;};

        string[] r = ["hello", "world"];

        auto r1 = reduce!foo(r); //<-- HERE

        auto r2 = reduce!(foo, foo,)(r);

        writeln(r1);

        writeln(r2);

    }

}