That repo is a bunch of TeX files (not even an implementation) that haven't been touched since 2018. I stand by my statement.
By the way, the Successor ML wiki says[1]:
> Standard ML, being incapable of evolution, is dead. The purpose of successor ML, or sML for short, is to provide a vehicle for the continued evolution of ML, using Standard ML as a starting point. The intention is for successor ML to be a living, evolving dialect of ML that is responsive to community needs and advances in language design, implementation, and semantics.
Again, I stand by my statement that Standard ML is dead.
SML/NJ, as I understand it, is implementing Successor ML features, so one of three things is true:
(1) Successor ML is happening,
(2) Standard ML is alive and evolving,
(3) SML/NJ isn’t just an implementation but a distinct language which is a successor to Standard ML and which incorporates what was described as “Successor ML”.
By the way, the Successor ML wiki says[1]:
> Standard ML, being incapable of evolution, is dead. The purpose of successor ML, or sML for short, is to provide a vehicle for the continued evolution of ML, using Standard ML as a starting point. The intention is for successor ML to be a living, evolving dialect of ML that is responsive to community needs and advances in language design, implementation, and semantics.
Again, I stand by my statement that Standard ML is dead.
[1] https://smlfamily.github.io/successor-ml/OldSuccessorMLWiki/...