segment

1 auto r1 = [0, 1, 2, 3, 4, 5];
2 auto s = segment!2(r1);
3 assert(equal(s, [tuple(0, 1), tuple(1, 2), tuple(2, 3), tuple(3, 4), tuple(4, 5)][]));
4 assert(s.length == 5);         // .length
5 // back/popBack:
6 assert(equal(retro(s), retro([tuple(0, 1), tuple(1, 2), tuple(2, 3), tuple(3, 4), tuple(4, 5)][])));
7 assert(s[3] == tuple(3, 4));    // opIndex
8 s[3] = tuple(0, 0);             // opIndexAssign not ref opIndex
9 assert(s[2] == tuple(2, 0));    // it affects its neighbors.
10 assert(s[4] == tuple(0, 5));
11 assert(r1 == [0, 1, 2, 0, 0, 5][]); // affects r1 back (no .dup internally)
12 
13 
14 auto st = ["a","b","c","d","e","f"];
15 auto s2 = segment!3(st);
16 assert(s2.front == tuple("a","b","c"));
17 
18 
19 auto r1 = [0,1,2,3,4,5]; // regenerates r1
20 auto s3 = segment!1(r1);
21 assert(equal(s3, [tuple(0), tuple(1), tuple(2), tuple(3), tuple(4), tuple(5)][]));
22 auto r2 = map!"a*a"(r1);
23 auto s4 = segment!2(r2); // On a forward range
24 assert(equal(s4, [tuple(0,1), tuple(1,4), tuple(4,9), tuple(9,16), tuple(16,25)][]));
25 
26 
27 int[] e;
28 auto s5 = segment!2(e);
29 assert(s5.empty);