You could wrap your operands in a type with a bind function that takes a function argument that has to be marked constant time. I guess it wouldnt strictly be a

You could wrap your operands in a type with a bind function that takes a function argument that has to be marked constant time. I guess it wouldnt strictly be a monad. You would then have to trust the implementor that he does not mark any non-constant time functions as being that, but I think that is reasonable.