FontoXPath 4.0 roadmap

[DrRataplan]

FontoXPath had made some unfortunate API choices over the course of its development. This issue holds all the places where we are planning to break for a 4.0 release

• Functions with prefixes. We have had an overload for registerCustomXPathFunction that accepts a URI, which is the preferred one. The old one has side-effects which are very dirty.
• Undocumented, unexpected behaviour of evaluateXPath without an expectedReturnType. This is done, The code needs to be removed, but we now have a better ALL_RESULTS type that is a lot better to use. See [minor] Add a new ResultType.ALL_RESULTS that does no magic #411
• Custom functions are registered in the global registry. These are side-effects and cause strange behaviour. We should externalize the state.
• Async query evaluation seems very useful, but it is not used. Decide whether we want to drop it this is being dropped in No more async #304
• Also remove the EvaluateUpdatingAsync / EvaluateUpdatingSync functions.
• ... More. This list will grow

[wvbe]

Linked to DEV-16792