On Wednesday, 18 July 2018 at 17:49:19 UTC, H. S. Teoh wrote:
On Wed, Jul 18, 2018 at 11:30:21AM -0600, Jonathan M Davis via
On the other hand, if opCmp is allowed to return a user-defined
type, it would solve the problem in a neat way: just define a
quaternary type that encapsulates the values -1, 0, 1, NaN, and
have opCmp return the equivalent of NaN for non-comparable
arguments. Then we could support partial orders correctly.
But I have a hard time seeing this actually work in practice,
because a user-defined return type for opCmp leads to recursion:
It already works with float, no recursion. A lot of the types I
use depend on this.
But having a language supported quarterny type would be good for
its improved speed.
