Wednesday, January 3, 2024

DAPLs: Domain Agnostic Programming Languages

Every once in a while, you get an insight that hits you like a truck. Or maybe a ton of bricks. Or a truck carrying a ton of bricks. Developing Objective-S has delivered a bunch of these, but one of the biggest was that our General Purpose Programming Languages are nothing of the sort. They are Domain Specific Languages for the domain of algorithms. See also: ALGOL. To move forward, programming languages will have to support more than just this one architectural style.

Alas, communicating this insight has been...challenging. One method was branding Objective-S as "the first general purpose programming language". This did not always go over well.

It looks interesting. But stuff like this:
> Objective-S is the first general purpose programming language
Those kind of statements annoy me to be honest. Is it really true? Or is it over-the-top marketing hype? For me – and I'm sure I'm not the only person who feels this way – it creates a negative first impression.
skissane on May 9, 2021 on: Objective-S: architecture-oriented language based ...

Of course, there is no such thing as bad publicity, but this had a bit too much of a lunatic-fringe vibe, no matter how correct the insight, and no matter how ill-fitting the moniker "general purpose language" really is for our call/return-oriented algorithm-DSLs.

As Richard Feynman once put it, "One of the miseries of life is that everyone names everything a litte bit wrong, and so it makes everything a little harder to understand in the world than it would be if it were named differently". Calling our algorithm-DSLs "general purpose" implies that we have solved the problem of generality, when we have not, and that the only real alternative is to be more specific, hence DSLs. But DSLs also don't really work that well, because the successful ones almost invariable grow non-domain-specific features, just in a haphazard way. Or they need to be combined to cover different fields, so we get language workbenches that allow us to define lots of little DSLs and combine them.

This all points to the fact that our problem is not being too general, but too specific. Our algorithm-DSLs just aren't very good at covering a lot of the problems programmers have to solve, though of course they are Turing-complete and can get us there, somehow.

Riffing off those ideas, and leaving aside the minefield of incorrect but entrenched terminology, I propose the term Domain Agnostic Programming Language. Because any sufficiently powerful DSL can be bent out of shape sufficiently for any purpose, just like our algorithm-DSLs can. They just aren't a good fit. And so Objective-S is not the first general purpose language, it is the first, and almost certainly the worst, DAPL. And hopefully its programming environment will be dapper.