So in other words, Raku is a better designed language.

Actually no. That is not the correct view.

Raku is actually a designed language. Perl is an accumulation of parts that mostly work together.

The main reason grammars are slow is because basically no one has touched the slow parts of it for the better part of a decade. We have some knowledge about how to speed it up because earlier prototypes had those optimizations.

The thing is, that it isn't that slow. Or rather it isn't that slow considering that you get an actual parse tree.

If you must know, the main reason it is slow is probably because it sometimes looks at particular tokens perhaps a half-dozen times instead of once. (This is the known optimization that was in one of the prototypes that I talked about.)

It has absolutely nothing to do with being able to replace what whitespace matches. That is already fairly optimized because it is a method call, and we have optimizations which can eliminate method call overhead. Since regexes are treated as code, all of the code optimizations can apply to them as well. Including the JIT.

Really if Perl doesn't do something drastic, in five to ten years I would suspect that Raku would just plain be faster in every aspect. (If not sooner.) The Raku object system already is faster for example. (And that is even with MoarVM having to be taught how Raku objects work every time it is started.)

Something like splitting up the abstract syntax tree from the opcode list. That way it can get the same sort of optimizations that Raku has that makes it faster than Perl in the places where it is faster.

Imagine if the code I posted would turn into something more like this:

loop ( my int64 $i = 1; $i <= 1_000_000_000; ++$i ) {}
[download]

It seems like every year or two we get a new feature or a redesign on a deep feature that speeds some things up by a factor of two or greater. Since Perl is more stratified than designed, it is difficult to do anything of the sort for it.

Also I don't know why we would want to downgrade to LLVM. (Perhaps it can be made to only be a side-grade.)

As far as I know LLVM only does compile-time optimizations. The thing is that runtime optimizations can be much much better, because they have actual example data to examine.

Perl is an awesome language.
Raku is an awesome language in the exact same ways, but also in a lot more ways as well.
Many of those ways make it easier to produce faster code.