Yes, that's exactly how it works. See this article for an example: http://nikita-volkov.github.io/refined/ http://nikita-volkov.github.io/refined/ The thing is

Yes, that's exactly how it works. See this article for an example: http://nikita-volkov.github.io/refined/ http://nikita-volkov.github.io/refined/ The thing is that, instead of redefining everything yourself, you could use a library that provides you with a set of predicates to compose and build the refinement you need. There are also much sophisticated ways to do this, like Liquid Haskell.