Function map3

tests/TestGeneric.cpp:165–166

"import std.random;\r\n\
void map1(auto[] arr, void ref(auto ref) f){for(int i = 0; i < arr.size; i++) f(arr[i]);}\r\n\
void map2(generic arr, generic f){for(int i = 0; i < arr.size; i++) arr[i] = f(arr[i]);}\r\n\
void map3(generic arr, generic f){for(int i = 0; i < arr.size; i++) f(arr[i]);}\r\n\
int[] arr = new int[1024];\r\n\
for(i in arr) i = rand();\r\n\
map1(arr, <int ref x>{ *x = -*x; });\r\n\