ddash.algorithm.flatmap

1 auto dup(int n) {
2     return [n, n];
3 }
4 
5 assert([1, 2].flatMap!dup.equal([1, 1, 2, 2]));
6 
7 import optional: some, no;
8 
9 assert([
10     no!int,
11     some(3),
12     no!int,
13     some(7),
14 ].flatMap!"a".equal(
15     [3, 7]
16 ));