There's a few on my radar (from most underestimated to popular):
- Pony (seems like the best of Rust and Go), need to build up adoption, libraries
- F#, what I wish my foray into Scala was like
- Elixir, possibly with Phoenix grow to be the next Ruby/Rails
- Julia, the only other data == code language (now has axes for 0-based indexing)
- Clojure, a batteries-included lisp
The biggest problem with F# for me originally was being tied to the Windows .Net platform. Now as mentioned it's from being in the shadow of C# which is incrementally getting features from F# in poorer form. It works fine on Mac and Linux but is still not easy to set up and get started.
I've recently seen Julia and Elixir mentioned in language discussions about homoiconicity. They're technically not--in the same sense as much as Lisp's s-expressions, but are convenient to do run-time code inspection and generation without much fuss which is the pragmatic side of it.
While normal Julia syntax is indeed arguably not quite homoiconic in the same way that Lisp s-expressions are (a good discussion of the issue by Stefan Karpinski here: [1]), it turns out there is a little-known built-in s-expression syntax for Julia (which can be more-or-less enabled as a REPL mode in only a handful of lines [2]).
I feel like the difficulty of getting up and running on linux also played a large role in F#'s relative unpopularity. I tried for several years, with one or two year gaps in between attempts, and the development experience was never very satisfactory. might be better now with .net core being given better linux support, but it was definitely a missed opportunity for the language.
Yeah, I tried out F# within the last year or so on Linux and it was fine. The setup, either Windows or Linux however was quite confusing. I was never really sure if I had all the right parts in place or ran all the right commands from the right places. Once it worked the first time, the development flow was good. I was doing simple compute, print self-learning coding, as well as making a web app with an sql db using Giraffe.
Back in the days when 'home computers' became a thing, and RAM memory cost roughly $100 per kilobyte, the race was on to produce a programming language that was good enough, and small enough to fit in a 4-kilobyte space.
Today, with GIGABYTES of RAM in even the least expensive computers, we have all sorts of new-fangled languages. But none, in my opinion, as underated as the BASICs of the 1970s.
