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Damian Conway Publishes Exegesis 5

Posted by michael on from the stick-to-coding-thanks dept.

prostoalex writes "Come gather round Mongers, whatever you code, And admit that your forehead's about to explode, 'Cos Perl patterns induce complete brain overload, If there's source code you should be maintainin', Then you better start learnin' Perl 6 patterns soon, For the regexes, they are a-changin'. This remix of Bob Dylan serves as an epigraph to Exegesis 5."

2 of 125 comments (clear)

  1. Perl6 FAQ by ajs · · Score: 5, Interesting
    Perl 6 is a big scary beast that sets people off in a lot of ways. Let me try to answer some of the big questions:
    • Why is Perl changing so much?!

      Because it needs to. Perl is the legacy of something like 15 years of development and evolution. It started as a simple text processing system, and is now used in every field of endevor where computers are used. There are some old things that needed to go, some new things that were needed and generally a need to re-examine the way "stuff" was done.

    • But what about my programs? Why break them?!

      Perl 6 is two things (at least): a parser for Perl 6 and a back-end virtual machine, much like Java or C#. One of the design criteria for the release of Perl 6 is a Perl 5 compatible parser front-end that outputs Perl 6 virtual machine bytecode. This means that your Perl 5 programs will run with no modification in a Perl 6 environment (or at most a path change to the interpreter, that much is still under some debate).

    • Why would you want to break compatibility with other regular expression engines?

      Remember that Perl has been leading the pack in terms of regular expression handling for a long time. Now Perl is moving beyond regular expressions to grammar specification. This is a good thing, as long as the benefits of regular expressions are preserved.

    Some of this will be good for everyone. Some of it some of you won't like, but a lot of it you will. Give Perl 6 a chance, and don't react as if we've shot your pet.
  2. Wow. A perl 4 geek's summary by dschuetz · · Score: 5, Interesting
    [preface:
    I first used perl back in version 3, something like 12 years ago. I first really learned perl, v4, about 9 years ago. It did everything I ever needed.

    Then, perl 5 came out. I didn't bother "learning" it -- that is, I've been using it, and when I really need to, I've used some perl 5 features, but I've learned them as I go (by example), and I know I'm not really using the full capabilites. (plus, though I know what I'm doing, I don't always know what to call what I'm doing -- I got stumped the other day when someone asked me how to do pointers in perl. I drew a blank, not making the connection to all the weird hash magic I'd been doing lately. But I digress.)

    Anyway, the bottom line of this is: Perl 5 looked interesting, but like more of the same, and wasn't really compelling for me to buckle down and learn all the new features. Perl 6, on the other hand, scares me. In a good way.

    Here's a page-by-page description of how I read the article:
    • Page 1: Hm. Looks like they're describing a grammar with regex. Cool.
    • Page 2: I can intuitively match against a set of strings! Wild. These strings can be expressions themselves? Even better!
    • Page 3: It's a grammar. A full, honkin, real, honest-to-goodness grammar. That I can match against. Are those angels I hear singing?
    • Page 4: <head explodes>
    • Page 5: <drools>
    Seriously, though, I was concerned at first that I'd have to learn something new, crazy, and difficult (given how screwed-up much of perl 5 has seemed, at times). I'm impressed. I'm very impressed. Yes, I have to learn somthing new and crazy, but it's not at all difficult. In fact, I think I've already learned it.

    The power that this new system holds, and, more importantly, the simplicity of it all, is amazing.

    So, unlike some other posters, I can't wait for Perl 6. When does this come out, again? And, more importantly, when can I buy the new book?

    (also, was I the only one who expected, after the demonstration of matching method invocations, to be told that the entire source code for perl6 was just one giant RegEx/Grammar?)