Is it possible to make refinement types in typed racket? Say I have a 500x500 pixel square, I want to define snap-to points every 5 pixels. I would like to be able to create a type that is a subtype of Integer instead of having my points be from the set of all integers (or even positive integers). Is it possible to define that a type is a subtype of positive integers and passes a certain predicate test like being divisible by 5 and less than 500?

@david.alkire yes, see http://docs.racket-lang.org/ts-reference/Experimental_Features.html?q=Refine#%28part._.Logical_.Refinements_and_.Linear_.Integer_.Reasoning%29

@samth that’s terrific. thank you so much for the link