Despite of the notation issues of existing Julia macro libraries for pattern matching,
based on my experience as a concerned user and developer, I hereby propose 4 major problems preventing us from bringing out good enough pattern matching, which I hope the authors and contributors of existing and future pattern matching libraries could pay attention to:
Optimizations: merging and splitting (EDIT addition) cases/patterns using algorithms of analysing decision trees, thus users won’t need aware how to write efficient code but how to write readable and maintainable code.
Portability. Expanding match macros usually needs non trivial analysis of the code, and this could be really time-consuming. As a result, debugging can be really slow and disturbing. My personal suggestion is making a small set of a pattern matching library “develop time only”, which just statically generates julia code without
Extensibility. The capability of defining custom patterns counts, because the demands of practical developments vary from the fields we work on, and one can never say he/she has known all fields of software developments and she/he has already made the useful pattern matching facilities for all those fields. One way to address this is providing a convenient way to define domain-specific patterns, which is called extensible pattern matching. And something called first class pattern matching is also helpful to this case.
Error reporting(Maintainability). The failure information of matching helps us to understanding the incorrectness in our code, and if the information doesn’t make sense, users will feel awful about the experience. It also closely concerns the maintainability and reliability of our code. IMO, we need source code positions, representation of the pattern in which the failure occurred, and the potential solutions to solve.
The idea was originally posted at https://github.com/RelationalAI-oss/Rematch.jl/issues/27#issuecomment-583914936 , and I appreciate Match.jl, Rematch.jl and other libraries whose contributors have spent time with this field.
Feel free to come up with more potential problems of Julia pattern matching.