klister VS rakudo

Yeah, that project is pretty much at the bottom of my list, unfortunately. My top projects these days are mgmt, klister, recursion-schemes, and hint... And that's already too much!

case is a special form, ie a bit of core syntax, but, interestingly, data is not. (It is presumably a macro; typechecking is actually done as a part of macro expansion.) The syntax remains pretty uniform. Or, in Klister, type ascription is done via normal S-expression syntax with a form called the, as (the $type $expression); again, the syntax is uniform.

Shameless plug: we don't have that problem in Klister, because our equivalent to main is a run macro which runs an IO action, and your alternate prelude can define its own run macro which expects an IO action from your alternate prelude.

Klister is very similar to Hackett, but implemented in Haskell instead of Racket, and my most recent PR is from 20 days ago, if that's the metric which counts for you. Still very much of a WIP though.

You might be interested in Klister: https://github.com/gelisam/klister

I've now also found an implementation for klister, which is meant to interleave type checking with macro expansion.

In Klister, which already has Scheme-like macros and Haskell-like types (polymorphism, algebraic types and higher-kinded types, but not yet fancier types like RankNTypes and GADTs), our plan to get the best of both worlds (lexical syntax and typed ASTs) is to separate parsing from macro evaluation. That is, users write their programs using the surface syntax of s-expressions, parsers parse those into typed ASTs, and macros are typed by the type of the ASTs they receive as input and produce as output. At this stage this is only a research idea, I don't know if that's going to work out yet, but I hope so!

Fix IO::Path::parent #4795: merged 2022-02-19 Add more IO::Path::parent tests #801: merged 2022-02-19 Change parent to always just remove the last element #4800: merged 2022-02-26 Change .parent behavior to "stupid" resolving #802: merged 2022-02-26

This then became the Formatter class. And since this was a completely new feature, it only became available for use by opting into the 6.e.PREVIEW language version. And then it went largely unnoticed and uncared for the next 1.5 year. As clearly the time wasn't right for it yet.

The intended audience are those people willing to be early adopters of these exciting new features in the Raku Programming Language. The examples in this blog post will work in the next release of the Rakudo compiler (probably 2023.06), but are now already available in the bleeding edge version.

If you really want to look at this, you can find the code in src/Perl6/Grammar.nqp, src/Perl6/Actions.nqp and src/Perl6/World.nqp.

If you find this very interesting, you probably want to read the RakuAST README. And the actual source code of the RakuAST classes can be found in the same directory. And if you're really feeling adventurous and you have the Rakudo repository checked out, you can have a look at the generated NQP code in gen/moar/ast.nqp.

Yes, it would. But until there was RakuAST, that was virtually impossible to do because there was no proper API for building ASTs. Nor was there an interface to execute those ASTs. And now that there is RakuAST, it is actually possible to do this. And there is actually already an implementation of that idea in the new Formatter class. Although this is definitely not intended as an entry point into grokking RakuAST.

I have opened one. https://github.com/rakudo/rakudo/issues/5205.

Will Coleda has made a Pull Request

There's an issue pertaining to this. This is something I'd like to resolve, but I'm unsure on how to better debug this to see if it really is the deserialization of a setting file triggering it. JDK 11 should at least be capable of building Rakudo, but being an experimental backend people don't always align with MoarVM immediately, I can't make any guarantees about tests. You may be disappointed in its performance at the moment.

(NB. While the PL is just a toy (and just a tiny bit of the toy too), the tech is actually industrial strength, used to power the production Raku compiler, which is written in Raku using its grammar construct. Starting easy doesn't mean you can't go far. Quite the opposite in fact -- you can go as far as you want.)