I was fortunate enough to use lisp professionally for nearly 20 years. The only reason that gig ended was the unfortunate demise of the majority owner and founder, and his heirs selling the shop to a competitor that only wanted the customer database imported. Lisp was never the problem, nor particularily messy.

On the contrary, we considered it a major reason we were able to build a quite successful stock broker and bank from scratch with a team of 4-6 people, who doubled as datacenter ops (we ran on-prem), internal tech support for the rest of the firm (~20 people) and 2.line customer support.

We quite naturally converged on a set of internal libraries for various tasks. Understanding and fixing each other’s code was not a big deal.

Coincidentally, our frontend was php. That was messier, and we conciously kept that layer as lean as possible.

The problem is that the type of developer you're talking about is the kind who invents a thousand excuses about anything. It doesn't begin and end with different languages. Using a different subset of their favorite language? A different toolchain? A radically different build process? You'll hear plenty of whining about it. Even just moving them to a different codebase will make them miserable. You put a Lisp or a Prolog in front of them, and their attention flows upwards to the most general principles to whine about. The entire thing is that if you stick them into an unfamiliar environment, they will vocalize their discomfort through rationalization. I think most people who have led teams will know exactly what I'm talking about.

Not that these people are necessarily bad at their jobs, but they're definitely a personality type you should learn to identify so you can manage them properly.

I use Common Lisp at work.

I disagree with this profoundly. There is no argument that Lisp in general can get you in a terrible mess. So can C, or pretty much any language (I well remember a case of 11-way multiple inheritance in C++ game code). If I were running a Lisp-based project, there would be project standards (like no exported macros without signoff, and a list of standard library dependencies), documentation requirements, and code review.

The fact that Lisp is the “programmable programming language” doesn't mean that every engineer should be inventing weird versions of while loops. What it does mean is that a skilled Lisp programmer can build a domain-specific language that substantially helps in development.

One good example of this is the Crash Bandicoot games, along with the same studio's Jax and Daxter, which were built with dialects of Lisp (yes, they had to compile the code, and take care with storage allocation, just like any other game code). Cisco hired Kent Dybvig, principal author of the Chez Scheme system, and open-sourced that software; I have no clue what they use it for, to be honest, but I assume that they had some reason for doing this. Companies using various Lisp languages have been documented in areas from fintech to quantum computing.

>> said: lovely, but I ain't using it at work.

Says who, you? Wrong. I use Common Lisp at work.

edit: and not just use as in a side toy, design and writing software in CL is my primary responsibility. FWIW, at a FAANG!

> The very power of Lisp, macros, dynamic programming, reflection lead to a mess of an ecosystem where every single developer reinvents the wheel and nobody can understand yet another DSL invented by the next developer next to them.

Have you like looked at anything in the Clojure ecosystem because this description makes no sense of any kind. Clojure has macros but less powerful than common lisp and Clojure code in the ecosystem tends to be small and understandable.