looking for a predicate hierarchy

I am looking for a library (of an OO language) which uses a hierarchy of classes for predicate (type) dispatch in the context of multimethod. Ce concept is already well know and developed in the literature, but languages which support multimethods and metaclasses are not so common. Therefore, I have some difficulty to find such 'standard' use of class as predicates. The papers usually use hierarchies inspired from specific taxonomy (e.g. animals) which are not general enough to be useful.

For the moment in my lib I have (<- means 'inherits from'):

Predicate (root class)
<- Nil
<- TrueFalse
<- True
<- False
<- Ordered
<- Lesser
<- Equal
<- Greater

But there is a lot of other possible predicates (not all useful):

Next, Previous
Forward, Backward
Open, Close
Front, Rear
Bottom, Top
Before, After
Up, Down
Even, Odd
Left, Right
North, South, Est, West

etc...

and selecting the predicates general enough (aliases and user defined predicates are always possible as extension) is somehow a problem of experience. BTW, the hierarchy stigmatize the possible logical combinations of the predicates (not, and, or) and strengthens the importance of its design (e.g. TrueFalse != Boolean).

Has somebody already seen such hierarchy? Links and references would be really appreciated. Thanks.

a+, ld.
.

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