Standard ML is almost the perfect language—functional-first without all the heavyweight and seemingly endlessly proliferating categorical abstractions which keeps the level of knowledege one needs to be productive low. Plus it’s easy to drop into old school imperative code when needed.

The only thing holdong sml back in my eyes is somewhat clunky syntax and the module system—which is great at first but quickly becomes tricky once you start having to use functors.

A modern, reimagined sml that keeps its core while adopting some of the nicer syntactic improvements from other langs in the family and improving the module system would be a god send

SML modules are a classic example of a "shadow language" ( https://gbracha.blogspot.com/2014/09/a-domain-of-shadows.htm... ). I'd like to see an ML-like language where modules/interfaces are normal values, functors are just normal functions, etc.

Modeling such a system at the value level is easy enough, but having it run at compile-time introduces some tricky issues (especially around IO).

The module syntax is certainly clumsy in comparison to the rest of the language, and it's not just the syntax - everything about functor arguments is a bit murky.