Why Lisp?

> So if that's what you want, why are you not just using Erlang?

I do.

> Why are we having this discussion at all?

I saw an article praising LISP, I decided to chime in with realism because certain fandoms (LISP's included) seem very unaware of the realities of the commercial programming outside of their niche hobby language. As a senior dev (who also worked as a CTO a few times) I have learned to evaluate technology and to never wear rose-tinted glasses even for my favorite tech stacks. They became favorites based on merit and nothing else. (In fact I am starting to dislike working with Elixir for certain projects, even though I loved doing them with it in the past.)

LISP is not cutting it for commercial work in general, so I strive to bring nuance to articles (or discussions) that to me seem heavily tilted to the "I am a fan!" direction. And forgive me if "LISP has longevity" and "it's future-proof" seem like hand-waving to me. I don't see factoids, I see people reinforcing their own positive feeling based on actual factoids (like the powerful macro system and a REPL, for example).

And we keep chatting because you seem to insist that either LISP has what I deem good (disagreed, it doesn't) or that it's not important / there's no market for it (disagreed).

> There's no market for it.

You're doing post-hoc rationalization. You don't know that for a fact. I know I would have coded much more Racket and Gerbil Scheme if they had proper async runtime a la Erlang or Golang or Rust (OCaml these days as well though the story there is still unfolding after their recent 5.0 release).

> You can't do better than Erlang at "Erlang-style concurrency" by definition.

Loose definitions then. Rust and OCaml are making very serious strides. I have hope they can surpass Erlang in the next 2-5 years. Both are faster, much stricter with types (lack of those is an endless pit of bugs) and more memory-safe than Erlang (though anything with a GC like OCaml is prone to some of the nastiest problems Erlang has, like cycles between big objects but... topic for another time).

> The point of Lisp is not do X-style-anything better than X. The main benefit of Lisp is that it allows you to explore a much larger space of possible solutions in a much shorter time, which is a big win when you don't know what you want, which, I submit, is most of the time.

We finally got somewhere productive, thank you.

I use Elixir (lives in the Erlang's BEAM VM so has access to everything Erlang) for the same and I agree that being able to explore quickly is very valuable. I've only made the mistake to prototype stuff with Rust once. Never again. Nowadays I use Elixir and Golang for prototyping and the end products either remain that or get rewritten in Rust.

Also REPL story can be better with Clojure but I'll admit it at least exists, unlike that of many other languages. Startup time is not ideal but then again, neither is Erlang's sadly. Editor support I haven't checked in a long time, might be good. Library coverage is very hit and miss depending on which LISP you use. I keep hearing CL has a lot, maybe that's true but I am 50/50 there; judging by your attitude -- "it took me a day to roll it myself" -- I remain unconvinced that the library story is good, it's more like some pie-in-the-sky goodness that's eternally out of reach. Still, if I reach for LISP again in the future I'll evaluate that aspect in detail and will know for a fact.

So yeah, on the "LISP is quick to prototype stuff with" I agree completely. To me it doesn't go all the way however, hence my initial comment.

You can think of me as "dislikes anything that looks like shilling".

There is no place for feelings in our work. When I retire and if I still want to code then, maybe I'll make decisions based on feelings. Before that -- no.

I know, I enjoy CL quite a bit. I actually currently have REPLs running for a few services, because I like managing them from the inside. But while you can, if you want, deploy major changes by redefining a bunch of stuff on production servers without version control or backups, you...should not.

It's really nice to be able to redefine classes while you're playing around- but CL's handling of class redefinition just isn't up to snuff on a production server. It's just like doing live changes to your schema, only you see, rather more so. Compared to scp->shutdown->mv->start, if you can possibly tolerate If you had to pick between having REPL access in production and REPL access locally, would it be close? Because I value being able to mess around with a REPL while developing thousands of times as much as I like a neat toy in production. And that ability is exactly what Python or Ruby or Erlang give you. Technically lacking compared to the full suite? Perhaps. But we're talking 0.999, not 0.5.

I think this is mostly an issue of tooling! I admit I often find myself recompiling a full file because SBCL is just so goddamn quick it doesn't make a difference, so perhaps I'm missing something essential. But with tree sitter you could totally write a plugin to, say, run the literal content of a python expression in the REPL. It's just shuffling text around after all. The fact that people haven't done this may indicate, and I stress may, that this is not something that people are missing.

I personally can't use anything without vim bindings. I have evil mode in Emacs, vimium while I'm in Firefox, vim bindings in Nyxt, and an aversion to using any program that isn't one of the above. This is not just hipsterism- on 10 occasions while writing this comment I've had to delete a kj or jk as I tried to exit edit mode. That doesn't really mean non-vim bindings are defective, if you catch my drift. No judgement here! But it's a possibility you might consider.

Ohhh, I wondered why people were so hyped about that! In my head I rounded it off to not wanting to recompile the whole file- I should have realized how dumb that was. This actually makes a lot of sense. When I helped a friend set up Calva, a part of me was really just assuming it was misconfigured- but no, it's designed to facilitate this kind of editing.

Though, I must ask, is it really that much better? I do keep functions around if I think I'll have a use for them again- the vast vast majority really are one-offs. Plus, most of my REPL usage is iterating on an expression. Obviously it's handy to edit it in place, but it's nice having multiple versions, even multiple trees, without having to relocate a cursor or undo unrelated changes.

[see cousin comment for my admission of stupidity]