What makes it viable for me in a professional setting isn't popularity, but rather any of the following: - Is it a first class citizen for the given platform?

What makes it viable for me in a professional setting isn't popularity, but rather any of the following: - Is it a first class citizen for the given platform? (What C# is to Windows, or Objective-C/Swift to macOS, or C to UNIX, or JS to the browser) Really can't go wrong with this one - Does it have a commercial vendor? (VFX Forth, SwiftForth, LispWorks, Allegro CL, MATLAB...) - Does it have a standard? (Probably less relevant these days but still a big plus to me) Things like libraries and all that I can do without. They're mostly terrible / too generic anyway. Note that some languages I use such as Go, Rust and OCaml don't really check any of the above, unless you nitpick. But it's not like I'm writing software with those for the long run (I'm old enough in the industry to think in terms of decades, and I've been burned by hype trains before).