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Ron Savage

  • Website: savage.net.au/
  • About: I try to write all code in Perl, but find I end up writing in bash, CSS, HTML, JS, and SQL, and doing database design, just to get anything done...
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  • Matt S Trout (mst) commented on Perl's Pegex Module: a great way to parse files by creating grammars

    I'm afraid that article doesn't seem like a convincing argument unless you accept the author's premises a priori. Certainly the second example (A = "a"A"a"/"aa") was entirely obvious to me, and yet was clearly chosen to try and demonstrate a problem.

    I think a clearer comparison of the strengths and weaknesses of PEG and Marpa, preferably with input from fans of both styles, would be a useful thing, but dismissing somebody's working code as a waste of time doesn't really count.

    -- mst

  • Jeffrey Kegler commented on Perl's Pegex Module: a great way to parse files by creating grammars

    Thanks for looking at my piece. Most users will read the PEG A = "a"A"a"/"aa" as if it was BNF or a regex, in which case the number of "a"'s clearly must be a multiple of two. But to match in PEG, the count must be a power of two.

    This was not obvious to the author or referees of the article from which I took the example. It is shown by formulating and solving a recurrence. The mathematician John von Neumann was famed for his ability to formulate and solve these off the top of his head, but I wonder if you perhaps, at this point in my article, read me a bit has…

  • Matt S Trout (mst) commented on Perl's Pegex Module: a great way to parse files by creating grammars

    Ron: If the article was insufficient for *me* to understand why you think PEG is "dangerous", I fail to see how it's going to help beginners at all.

    Jeffrey: Nah, I read it as a regex-like thing and got the right answer immediately - a *multiple* of two would obviously require "aa"A/"aa" or similar, no? I think perhaps it might be an interesting exercise for you to show a few more "intuition defying" examples to a few perl hackers some time and see whether it truly defies intuition in general or merely *an* intuition, and we have a different one.

    -- mst

  • Jeffrey Kegler commented on Perl's Pegex Module: a great way to parse files by creating grammars

    Intuitions certainly can differ. I may add more about PEG to my "Parsing: A Timeline" piece: http://jeffreykegler.github.io/Ocean-of-Awareness-blog/individual/2014/09/chron.html PEG's algorithm in fact goes back to the pre-YACC compiler-compilers of the 1960's.

  • quepadretanpadre commented on Using Padre for the first time

    i have version .94 that came with dwimperl
    for windows

    when i have multiple files open, and i close
    any one, padre closes altogether
    it's very annoying, and pretty much renders padre
    useless as far as i'm concerned.

    thank you for this website

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