Langs and slangs

[masak]

I've had what I think is a conceptual breakthrough on slangs. Detailing it here.

Posit, for a moment, that there's not just slangs, but also "langs". I'd argue that this concept exists already, but didn't really have a separate name.

I see two main ways langs are different from slangs:

1. In BASIC terms, a lang is a GOTO and a slang is a GOSUB. You expect to switch into a lang but not back. With a slang, you switch back at some point.

2. A lang is "top-level" but a slang has an implicit — I don't have a good term for this yet — "outer environment", the lang or slang from which it was invoked.

Both langs and slangs have a thing in common — they are formed around grammars and the downstream processing into ASTs and fine-grained instructions. Functions, type declarations, and macros on the other hand extend an existing language out on its fringes. Langs and slangs start from a clean slate (though of course they can inherit from other langs and slangs if they want).

So, donkey-bridge explanation: a slang is "ok, let's open up a block of SQL here"; a lang is "it's time to be Prolog now".

Going to close this issue immediately as lacking a real observable. But I would like to see an implementation of the lang import idea, in some form. Even if it's faked at first.