http://www.perlmonks.org?node_id=43334

Leitchn has asked for the wisdom of the Perl Monks concerning the following question:

OK - I know there are various tools out there to do this, but I need to do it myself.
So here goes......

What I'm currently trying to do is get the children from this line in a DTD file:

<!ELEMENT ORDER    (NAME,DELIVERY,PAYMENT,ORDERNUMBER)>

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I'm currently drowning in regexps, and my current attempt is wildly off track - can anyone point out where I'm going wrong? 

while ($dtdLine=~/(\((.*?)\,|\,(.*?))/sg){
    push(@children,$1);
    print "@children\n";
}

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TIA

Nick.

Replies are listed 'Best First'.
Re: Using regexps to parse an XML DTD file
by the_slycer (Chaplain) on Nov 26, 2000 at 06:54 UTC
    Not what I would do ($1 is not neccesarily a good thing ;-)), but here's some code that works, note that it's not all a regex :-) 
    $string = "<!ELEMENT ORDER    (NAME,DELIVERY,PAYMENT,ORDERNUMBER)>";
$string =~ m/\((.*)\)/;
@array = split (/,/,$1);
foreach (@array){print "$_\n"}

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[d/l]
      Excellent, thanks - out of interest though, can it be done with a single regexp?

      Nick.
[reply]
        A single regex cannot generate a variable number of backreferences. What do you think this is, Java? 1{grin}

        -- Randal L. Schwartz, Perl hacker

        1The Java regex library I saw caused /(\w+)\s+)+/ to generate a variable number of backreferences, making it impossible to know exactly what part of the match you were looking at. Evil. They just don't get it.
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Re: Using regexps to parse an XML DTD file
by Leitchn (Acolyte) on Nov 26, 2000 at 06:40 UTC
    I'm getting closer: 

    $dtdLine=~m/\((.*)\,|\,(.*)\)|\,(.*)\,/sg)

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    Gives me all but the last one.
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Re: Using regexps to parse an XML DTD file
by Leitchn (Acolyte) on Nov 26, 2000 at 06:15 UTC
    I didn't really forget the 'm' after the =~.

    Honest.

    Nick.
[reply]

      If you hadn't of said anything we wouldn't have noticed; the 'm' in m// is optional and has been for a while : ) 

      <myExperience>
$mostLanguages = 'Designed for engineers by engineers.';
$perl          = 'Designed for people who speak by a linguist.';
</myExperience>

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