On 05/12/2013 02:09 PM, Paolo Bolzoni wrote:
> I need to user Red-Black trees with non-default sorting.
> Here is a minimal example
> ---- >8
> import std.container;
> struct CC {
> int a;
> int b; }
>
> bool less(const ref CC lhs, const ref CC rhs) {
> if (lhs.a != rhs.a)
> return lhs.a < rhs.a;
> else
> return lhs.b < rhs.b; }
>
> void main() {
> auto t = new RedBlackTree!(CC, "a.a != b.a ? a.a < b.a : a.b <
> b.b"); }
> 8< ----
>
> It works, but I would like to pass the function "less" as comparison
> operator since in my real problem the comparison is a more complex.
I think this is an issue with the template constraint of RedBlackTree.
It passes the alias template parameter through binaryFun and I think
that fails the check:
final class RedBlackTree(T, alias less = "a < b", bool allowDuplicates =
false)
if(is(typeof(binaryFun!less(T.init, T.init))))
A workaround:
auto t = new RedBlackTree!(CC, (a, b) => less(a, b));
Ali
