public Compositions <A> Append(Compositions <A> compx, Compositions <A> compy)
{
Seq <Compositions <A> .Node> go(Seq <Compositions <A> .Node> mx, Seq <Compositions <A> .Node> my)
{
if (mx.IsEmpty)
{
return(my);
}
if (my.IsEmpty)
{
return(go(mx.Tail, Seq1(mx.Head)));
}
var x = mx.Head;
var sx = mx.Head.Size;
var cx = mx.Head.Children;
var vx = mx.Head.Value;
var xs = mx.Tail;
var y = my.Head;
var sy = my.Head.Size;
var vy = my.Head.Value;
var ys = my.Tail;
var ord = sx.CompareTo(sy);
if (ord < 0)
{
return(go(xs, x.Cons(my)));
}
else if (ord > 0)
{
var(l, r) = cx.IfNone((default(Compositions <A> .Node), default(Compositions <A> .Node)));
return(go(r.Cons(l.Cons(xs)), my));
}
else
{
return(go(new Compositions <A> .Node(sx + sy, Some((x, y)), default(MonoidA).Append(vx, vy)).Cons(xs), ys));
}
}
return(new Compositions <A>(go(compx.Tree, compy.Tree)));
}