Emacs Lisp Elements

I've had a great time using Emacs Lisp over the past 15 years: it's one of the easiest ways to quickly whip up personalized tools for my own use, and, at the same time, my code has been surprisingly resilient and stable over this time.

And this is despite the fact that Emacs Lisp routinely flouts every single software engineering "best practice". The language is dynamically scoped by default! It simply doesn't have namespaces! Static types? Hah! (And I, an inveterate Haskeller, don't even miss them.) You can—and people routinely do—hook directly into all sorts of implementation details from other parts of the codebase.

And yet it just works. And it works remarkably well.

My theory: what matters isn't "best practices", it's have a coherent conceptual design and code that reflects that design. Emacs is designed around a small but expressive set of core concepts that it uses in a consistent manner. Text with properties, buffers, modes, commands, customization variables... Almost everything more complex in Emacs is structured out of these (+ a handful more), and, once you've internalized them, it's surprisingly easy to both learn new higher-level tools and to write your own.

The design of both the user interface and the code directly reflect these concepts which gives us a naturally close connection between the UI and the code (it's almost trivial to jump from an interaction to the code that powers it), makes both UI and code units effortlessly composable and generally makes it easier to understand what's going on and how we can change it.

> My theory: what matters isn't "best practices", it's have a coherent conceptual design and code that reflects that design.

Just because something has a >0 level of success doesn't mean there are no negatives. "Best practices don't matter because Emacs Lisp doesn't follow them and it just works" isn't a valid argument: it could very well be that Emacs (Lisp) would shine fifteen-fold brighter if it did also follow those practices. It just happens that having those elements you mentioned as positives are enough to keep the train going in spite of the shortcomings.

I use Emacs and program in Emacs Lisp to scratch my itches, and I agree that there are elements that make it work and hey, I'm still here, but I will bet good money that a parallel universe with Emacs Lisp', Now With Namespaces would work even better.

"Working" isn't binary.

That's certainly true!

But based on my holistic experience using Emacs—more than a binary "it works"—I'm convinced that the conceptual design carries most of the weight.

Would namespaces, lexical scoping, etc be better? Almost definitely. But it would be a marginal improvement, a difference in degree not kind. Other "best practices" like more aggressive information hiding would go against Emacs's design and make it worse as a whole.

Most "best practices" are neither necessary nor sufficient and, in most cases, not even particularly effective, even when they offer strict improvements over the status quo.

> Would namespaces, lexical scoping, etc be better? Almost definitely. But it would be a marginal improvement, a difference in degree not kind.

That's the thing - it probably would not be.

IMO, the key things that allow Emacs to succeed and last, while being somewhat unique in how it "routinely flouts every single software engineering "best practice"", are not merely conceptual, but cultural or even philosophical. The most fundamental of those, IMO, is that Emacs is ultimately owned by users, who are treated as intelligent partners in the relationship. Everything is designed with extensibility in mind. There's no hard boundary between "core developers", "third-party extension developers" and "end-users" - everyone can be any of them, including all three, at any time.

Maximizing extensibility and interoperability, not demanding "users" to coordinate with "developers" and ask for permission, not chasing user growth (it's all Free Software), expecting that everyone is a responsible adult, encouraging users to make Emacs "their own" - all that leads to an approach that goes the opposite to standard software development practice, because the standard practice is built around entirely opposite assumptions.