OK, here's an actual, compilable, runnable version:
import std.algorithm : sum;
import std.meta : allSatisfy, staticMap;
import std.range : only;
import std.traits : CommonType, isStaticArray;
alias Elem(A : E[n], E, size_t n) = E;
enum Length(A) = A.length;
enum sumLengths(A...) = sum(only(0, staticMap!(Length, A)));
CommonType!(staticMap!(Elem, A))[sumLengths!A] append(A...)(A arrays)
if (allSatisfy!(isStaticArray, A))
{
typeof(return) result = void;
foreach (i, a; arrays) {
enum offset = sumLengths!(A[0 .. i]);
result[offset .. offset + a.length] = a[];
}
return result;
}
@nogc unittest {
int[2] a = [ 1, 2 ];
int[3] b = [ 3, 4, 5 ];
int[4] c = [ 6, 7, 8, 9 ];
auto d = append(a, b, c);
assert(is(typeof(d) == int[9]));
assert(d == [ 1, 2, 3, 4, 5, 6, 7, 8, 9 ]);
}
T
--
Be in denial for long enough, and one day you'll deny yourself of things you
wish you hadn't.
