kitten VS magrittr

While not quite a Forth, Kitten is a stack language:

https://kittenlang.org/

Since you're making a statically-typed concatenative language, I'll point you to a joy reference, kitten, notes to motivate type checking stack languages, and a paper that formalizes type checking for stack languages. Since this looks like a relatively high-level stack language (given the presence of ADTs), you may find that you want to add quotes to your language, specifically opaque quotes since your language is typed. In that case, you'll realize that you'll need a better way to formulate polymorphism over stacks, and the paper on type checking will provide that to you.

Well, there is Kitten, although it hasn't seen an update in two years and was moving quite slowly before that too.

https://kittenlang.org/

Author ended up doing a lot of work on Kitten https://github.com/evincarofautumn/kitten

Kitten lang

You may like https://kittenlang.org/

R (yes, the statistics language) has exactly this.

You can literally extract the body of a function as a list of "call" objects (which are themselves just dressed-up lists of symbols), inject/delete/modify individual statements, and then re-cast your new list to a new function object.

I don't know why the original devs thought this was necessary or even desirable in a statistics package, but it turns out to be a lot of fun to program with. It has also made possible a wide variety of clever and elegant custom syntaxes, such as a pipe infix operator implemented as a 3rd-party library without any custom language extensions [0]. The pipe infix operator got so popular that it was eventually made part of the language core syntax in version 4.1 [1].

[0]: https://magrittr.tidyverse.org/

[1]: https://www.r-bloggers.com/2021/05/the-new-r-pipe/

In R (thanks to magrittr) you can now perform operations with a more functional piping syntax via %>%. This means that instead of coding this:

Try reading the documentation for magrittr.

Related note: the statistical programming language R has a library named magrittr to support the pipe operator.

About the pipe (%>%) symbol, it's provided by the magrittr package. The package documentation details how to use the pipe operator.

I was wondering what some good ways are to handle nested function calls without chaining them in long, ugly nested statements. I am looking for functionality similar to the pipe forward operator %>% in magrittr/R or |> in F#.

You may like R: https://magrittr.tidyverse.org

Agreed on everything else you said (especially the type safety stuff, it massively helps in production), but one correction: magrittr is absolutely in the tidyverse suite. It's not considered one of its "core" packages that it visibly tells you it loads, but magrittr is loaded when calling library(tidyverse) and development of the package is handled by the tidyverse team under their Github account: https://github.com/tidyverse/magrittr