Comment by olau

I like the explicit pipelining idea, seems much easier to reason about. Some comments:

I found the "# `|` can be used rather than newlines." a bit odd. So when using let, you're only transforming one column? I think the example would look weird with returns instead of |.

Depending on your intended target, it might help adoption if you stay closer to the naming conventions of that target. If you're targeting mainstream Java/Python/C#/Javascript etc. then functions need parentheses, "take 20" may be worse than slice, etc.

I think annotating microversions would get tiresome fast. I think the right way to think of this is that you put in a single version number like 1, and then only ever change that if you need to do backwards-compatible changes that cannot be handled by clever hacks in the runtime.

Also I think you should try writing one or more native wrappers in your intended target languages to make sure it's easy to interface between the two, even if it means you'd have to use dots in that language.

I could imagine an end game where the ergonomics were so good that a database like Postgres ends up with a native PRQL frontend. Not sure you're there yet, though. IMHO SQL as a query language suffers from a) sometimes really bad ergonomics, b) it's hard to wrap in another programming language (also ergonomics), c) it has far too many concepts - it's not orthogonal.