mlkit

This is a very cool project. There is also MLKit's SMLtoJs which compiles to Javascript, but not to Lua. https://github.com/melsman/mlkit/blob/master/README_SMLTOJS....

None of these are Standard ML! There are people who prefer SML for various reasons. Somewhat unexpectedly, there is in fact already a very good SML-to-browser solution, namely the unfortunately named SMLtoJs: https://github.com/melsman/mlkit/blob/master/README_SMLTOJS.... It's from 2011 and so predates most other Javascript-targeting languages. It's unfortunate it never got any traction.

Note that "pass by value" isn't a copy in a language with affine types like Rust. I'm not sure passing everything by reference probably would gain much in a systems programming language in the vein of Rust: one would still need some syntactic method to distinguish between shared ("immutable") and non-shared ("mutable") references. Also, Rust-style static reasoning cares about things actually being pointers, to allow returning references safely. Lastly, being able to move things around is important too, it is a major part in Rust creating zero-overhead abstractions. I'm not sure exactly how MLKit works, but I glanced over https://github.com/melsman/mlkit/blob/master/doc/mlkit.pdf and it seems to me that its regions are somewhat less static and that it doesn't attempt to handle concurrency. I could be wrong on both counts!

You can also compile Standard ML to Javascript using SMLtoJS [0] via MLKit [1]. melsman even has an online IDE [1] with which you can play around with his reactive web stuff. [0] http://www.smlserver.org/smltojs/ [1] https://github.com/melsman/mlkit [2] https://smlserver.org/ide/