#!/usr/bin/perl -w
use strict;
use warnings;

use Data::Dumper;

my $key;
my %hoa;

my @arr;
while ( <DATA> )
{   
   next if (/^\s+/);
   if ( /^SET/ ) {
     my @KEY = split (/[\s:]/,$_);
     $key = $KEY[2]; 
     @arr = (); # need to do this or get extra elements in second array. Try commenting this out... interesting
   } elsif (/^\d/) {
       my @INST = split(/,/,$_);
       push @arr, [@INST];
	}
   $hoa{$key} = [ @arr];
}
print Dumper \%hoa ;

__DATA__
SET: SET1

0,100,BOOK
1,150,PENCIL
====

SET: SET2

2,110,ERASER
2,200,PEN
0,220,BLACKBOARD
1,300,CHALK
====