Unusual Raku Features

I don't think we disagree here. To clarify, my statement about using "actual parsers" over regexes was more directed at my own library than Raku. Since I had just posted a link on how to "parse" media types using my library, I wanted to immediately follow that with a word of caution of "But don't do that! You shouldn't be using (traditional) regexes to parse! They are the wrong tool for that. How unfortunate it is that most languages have a super simple syntax for (traditional/PCRE) regexes and not for parsing." I had seen in the article that Raku had some sort of "grammar" concept, so I was kind of saying "oh it looks like Raku may be tackling that to."

Hopefully that clarifies that I was not necessarily making any statement about whether or not to use Raku regexes, which I don't pretend to know well enough to qualify to give advice around. Just for the sake of interesting discussion however, I do have a few follow up comments to what you wrote:

1. Aside from my original confusing use of the term "regexes" to actually mean "PCRE-style regexes", I recognize I also left a fair amount of ambiguity by referring to "actual parsers". Given that there is no "true" requirement to be a parser, what I was attempting to say is something along the lines of: a tool designed to transform text into some sort of structured data, as opposed to a tool designed to match patterns. Again, from this alone, seems like Raku regexes qualify just fine.

2. That being said, I do have a separate issue with using regexes for anything, which is that I do not think it is trivial to reason about the performance characteristics of regexes. IOW, the syntax "doesn't scale". This has already been discussed plenty of course, but suffice it to say that backtracking has proven undeniably popular, and so it seems an essential part of what most people consider regexes. Unfortunately this can lead to surprises when long strings are passed in later. Relatedly, I think regexes are just difficult to understand in general (for most people). No one seems to actually know them all that well. They venture very close to "write-only languages". Then people are scared to ever make a change in them. All of this arguably is a result of the original point that regexes are optimized for quick and dirty string matching, not to power gcc's C parser. This is all of course exacerbated by the truly terrible ergonomics, including not being able to compose regexes out of the box, etc. Again, I think you make a case here that Raku is attempting to "elevate" the regex to solve some if not all of these problems (clearly not only composable but also "modular", as well as being able to control backtracking, etc.) All great things!

I'd still be apprehensive about the regex "atoms" since I do think that regexes are not super intuitive for most people. But perhaps I've reversed cause and effect and the reason they're not intuitive is because of the state they currently exist in in most languages, and if you could write them with Raku's advanced features, regexes would be no more unintuitive than any other language feature, since you aren't forced to create one long unterminated 500-character regex for anything interesting. In other words, perhaps the "confusing" aspects of regexes are much more incidental to their "API" vs. an essential consequence of the way they describe and match text.

3. I'd like to just separately point out that many aspects of what you mentioned was added to regexes could be added to other kinds of parsers as well. IOW, "actual parsers" could theoretically parse Raku, if said "actual parsers" supported the discussed extensions. For example, there's no reason PEG parsers couldn't allow you to fall into dynamic sub-languages. Perhaps you did not mean to imply that this couldn't be the case, but I just wanted to make sure to point out that these extensions you mention appear to have much more generally applicable than they are perhaps given credit for by being "a part of regexes in Raku" (or maybe that's not the case at all and it was just presented this way in this comment for brevity, totally possible since I don't know Raku).

I'll certainly take a closer look at the full Raku grammar stuff since I've written lots of parser extensions that I'd be curious have analogues in Raku or might make sense to add to it, or alternatively interesting other ideas that can be taken from Raku. I will say that RakuAST is something I've always wanted languages to have, so that alone is very exciting!

Programming is not just a matter of slinging syntax at a problem. Good programmers need to develop a mental model of how a language works.

Needing to do geometric sequences as syntax like that is clearly a parlor trick, a marginal use case. What goes through a good programmer's mind, with experience of getting burned by such things over the years, is "If Raku implements this parlor trick, what other ones does it implement? What other numbers will do something I didn't expect when I put them in? What other patterns will it implement?"

Yes, you can read the docs, and learn, but we also know this interacts with all sorts of things. I'm not telling you why you should be horrified, I'm explaining why on first glance this is something that looks actually quite unappealing and scary to a certain set of programmers.

It actually isn't my opinion either. My opinion isn't so much that this is scary on its own terms, but just demonstrates it is not a language inline with any of my philosophies.

Java does have a particular blend of features and lack of features that has led to the bloated, boilerplate-laden, inflationary framework ecosystem around it that is worse that I've seen in any other language.

Lack of stack-allocated structs leads to object pooling.

Lack of named arguments combined with the tediousness of writing `this.x = x` over and over, along with the reflection system that Java does provide leads to IoT frameworks that muck about in your private variables and/or generate objects "for you"[1].

Lack of a way to mark object trees as immutable short of duplicating all the constituent classes leads to everyone generally assuming that everything is and moreover should be mutable, necessitating complex systems for isolating changes to object graphs (e.g. the way Hibernate supports transactions).

Etc, etc. I wrote a list of these things somewhere.

[1] "It does X for you" is a phrase I've heard too many times from coworkers trying to sell me on some framework that we didn't need. "Oh yeah, it does an easy job for me an in exchange I have an incomprehensible spaghetti mess to deal with, thanks." Being the only person in the room who notices the complexity monster growing bigger and bigger is a never-ending source of frustration.

Record classes alleviate the pain of writing immutable data object classes but are unfortunately late to the party.

> digressions into discussing Perl

Changing the name to Raku doesn't obliterate Perl 6's history as Larry Wall's successor to Perl 5.

I don't know why you would expect people to pretend that they're unrelated. They aren't.

To me it’s not unlike spending all of a thread about Clojure commenting on Java or Common Lisp without even bothering to mention or contrast to Clojure.

There are connections to both but that doesn’t necessarily make them topical.

I disagree that discussing a previous language by a designer (often in terms that seem to conflate equivalence) is usefully relevant to discussion of a different language by that designer.

Note that I have never said that there is zero utility. I just find it tiresome to encounter comments about Perl syntax as if it is automatically useful or interesting to discussions about Raku.

Which is why I took the time to provide an example of what (I would consider) an actually relevant mention of Perl syntax.