$ cat test4.d && gdc test4.d -o test4 && echo "----" && ./test4
import std.stdio;

T[][] group(T)(T[] array) {
  T[][] res;
  foreach (index, elem; array) {
    if (index == 0 || elem != array[index-1])
      res~=(T[]).init;
    res[$-1]~=elem;
  }
  return res;
}

void main() { writefln(group("ZBBBCZZ")); }
----
[Z,BBB,C,ZZ]