Re: Slides from LASER 2012

[Timon Gehr]

On 09/20/2012 11:33 PM, bearophile wrote:

Timon Gehr:

mixin ADT!q{ Tree(T): Leaf(T x), Node(Tree a, Tree b) };

DynRange!T fringe(T)(Tree!T t){
    return t.match!(
        (Leaf l) => cons(l.x, empty),
        (Node n) => chain(n.a.fringe, n.b.fringe).dynRange,
    );
}

bool sameFringe(T)(Tree!T t1, Tree!T t2){
    return equal(t1.fringe, t2.fringe);
}

What's the purpose of the dynRange suffix here?
(Node n) => chain(n.a.fringe, n.b.fringe).dynRange

chain has type Result. dynRange takes an arbitrary range and transforms
it into a range with the same value/vs reference behaviour whose static
type depends only on the element type.

Maybe a "~" operator can be defined for such dynRanges, to avoid the
chain().

Yes, that should certainly be done. (it can be more efficient.)