This by no way the finish product but it may help you get started.

#!/usr/bin/perl -w
# 
use strict;
my ($xmlvar,$i,$k,$v); 
my %hash = ();
while (<DATA>) { print;
    chomp($_);
    $i = 0;
    while ($i++ < length($_)) {
        print "1: '";
        print $1 if /(<)/gc; print "', pos=", pos, "\n";
        $k = '';
        print "2: '";
        $k = $1 if /\G([A-Za-z0-9]+)/gc;  print "$k', pos=", pos, "\n"
+;
        my $f = '</'.$k.'>' if defined $k;
        print "3: '";
        print $1 if /(>)/gc; print "', pos=", pos, "\n";
        $v = '';
        print "4: '";
        $v = $1 if /\G(.*)$f/gc; print "$v', pos=", pos, "\n";
        $i = pos;
    print $k,' << ',$v,"\n";
    $hash{$k} .= $v.','if defined $k;
    }
    print "Final: '$1', pos=",pos,"\n" if /\G(.)/;
}
s/,\z// for values %hash;
while ( my ($key, $value) = each(%hash) ) {
      print "$key => $value\n";
      }

__DATA__
<dataset>
 <row>
  <name>dog</name>
  <category>home pet</category>
 </row>
 <row>
  <name>cat</name><category>home pet</category>
 </row>
 <row>
  <name>penguin</name>
  <category>fish</category>
 </row>
 <row>
  <name>lax</name>
  <category>wile</category>
 </row>
 <row>
  <name>whale</name>
  <category>fish</category>
 </row>
 <row>
  <name>ostrich</name>
  <category>bird</category>
 </row>
 <row>
  <name>catfish</name>
  <category>fish</category>
 </row>
</dataset>
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