[spockz]

In the article you (auxon) wrote to avoid using type based generators and unbounded collections and instead write your own generators. Usually I find it more convenient to write filters on the generated types then create my own generators. As the post mentions, this can lead to many discarded inputs. Have you ever considered how we could use the predicates in the filters to create Specialized generators that only generate inputs that will be accepted by the filter? You probably need some meta programming or reification of the predicates for that to work.

[mristin]

You can already do that with a family of predicates if you write preconditions in your Python code (see my previous comment [1]). There is an ongoing discussion how to bring this in into Hypothesis (see the issue [2]).

[1]: https://news.ycombinator.com/item?id=26018386

[2]: https://github.com/HypothesisWorks/hypothesis/issues/2701

edit: newlines

[mullr]

> Have you ever considered how we could use the predicates in the filters to create Specialized generators that only generate inputs that will be accepted by the filter? You probably need some meta programming or reification of the predicates for that to work.

That's a really nice idea. It doesn't fit into the usual compositional design of the proptest libraries that I've used, but it certainly seems like it should be possible in principle.