More Perl regex stuff in E

[Bill Frantz]

At 11:21 PM -0700 4/15/99, Mark S. Miller wrote:
>I don't know whether to laugh or cry.  Before I started *using* Perl regular
>expressions in E, I felt my code was readable.  The following code doesn't
>look readable to me, but is this just because I'm not used to reading this
>style?  In any case, it's small, was easy to write, worked the first time,
>and does something a bit complicated: parsing updoc scripts.  It
>successfully parsed the output of html2txt() applied to some of my
>documentation pages.  If I'd tried to write this without regex's, it might
>be locally more readable, but would also be a lot more code -- an
>interesting tradeoff.  How does it compare with regex use in Perl or
>Python?
>
>Here's a readability test: By reading this code, can you easily tell what
>syntax it parses?

I can't write regex, nor read them.  I would need a complete accurate
description of the syntax to decode them.  (I assume that if a computer can
interpret them, I can too, but not by reading.)

>
>(If your mailer wrapped the lines, please unwrap them before reading)

I think your mailer wrapped them.  Anyway, they arrived wrapped.  (List
software?)

>
>
>define parseUpdoc(script) {
>    define result := [] diverge
>    while (script =~ rx`(?ms)(@comment.*?)\n?[ \t]*\?[
>\t]?(@code.*?)\n(@rest.*)`) {
>        script := rest
>        while (script =~ rx`(?ms)[ \t]*>[ \t]?(@moreCode.*?)\n(@rest.*)`) {
>            code += "\n" + moreCode
>            script := rest
>        }
>        if (script =~ rx`(?ms)[ \t]*#[ \t]+?(@label\w*):[ \t]*(@output.*?)[
>\t]*\n(@rest.*)`) {
>            script := rest
>            while (script =~ rx`(?ms)[ \t]*#[ \t]*(@moreOutput.*?)[
>\t]*\n(@rest.*)`) {
>                output += "\n" + moreOutput
>                script := rest
>            }
>            result push(CarrotMaker(comment, code, label, output))
>        } else {
>            result push(CarrotMaker(comment, code, null, null))
>        }
>    }
>    result snapshot
>}


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