#!/usr/bin/perl

use strict;

print qq{<?xml version="1.0"?>\n};
my $tag;

while(<DATA>) {
    chomp;
        if ( /^\[(\w+)\]/ ... /^\w+/ ) {
        $tag = $1 if $1;
        print "<$tag>$_</$tag>\n" if ( ! /^\[/ );
    }
}
__DATA__
[DATA]
data1
[ENTRY]
entry here
[STORY]
story details
[DATA]
[ENTRY]
another entry here
[STORY]
another story
[KEY]
[WRITER]
Han
Staff

##</code><code>##

<?xml version="1.0"?>
<DATA>data1</DATA>
<ENTRY>entry here</ENTRY>
<STORY>story details</STORY>
<DATA>another entry here</DATA>
<STORY>another story</STORY>
<KEY>Han</KEY>