# stringlist - full functionality list of strings class

package StringList;

use Data::Dumper;
$Data::Dumper::Indent = 0;  

sub new {
   my($class) = @_;   

   bless({stringlist => [],}, $class);
}

sub push { 
   my($self,$item) = @_;
   my($list) = $self->{stringlist};
   push(@$list,@$item); 
}

sub size { 
   my($self) = @_;
   my($list) = $self->{stringlist};
   return scalar(@$list); 
}

sub at { 
   my($self,$i) = @_;
   my($list) = $self->{stringlist};
   return $list->[$i]; 
} 

sub stringify { 
   my($self) = @_;
   my($list) = $self->{stringlist};
   return Dumper($list); 
} 

sub clear { 
   my($self) = @_;
   @{$self->{stringlist}} = ();
} 

sub elimdups {
   # eliminates duplicates from a list (aka make a set, make a list of unique items)
   # (note: was called uniquify...a momentary slip in taste)
   my($self) = @_;
   my($list1) = $self->{stringlist};
   my($hash1) = hashify($list1);
   my($list2) = listify($hash1);
   my($list3) = StringList->new();
   $list3->push($list2);
   return $list3;
}

sub sameitems {
   my($self,$stringlist2) = @_;
   my($hash1,$item);
   my($list1) = $self->{stringlist};
   my($list2) = $stringlist2->{stringlist};
   $hash1 = hashify($list1);
   foreach $item (@$list2) {
      if (!(exists($hash1->{$item}))) {
         return(0);
      }
   }   
   return(1);
}

sub hashify {
   # hashifies a list: (a,b) -> (a => 1,b => 1)
   my($list) = @_;
   my(%hash,@list2,$val);
   foreach $val (@$list) {
      push(@list2,$val);
      push(@list2,'1');
   }
   %hash = @list2;
   return \%hash;
}

sub listify {
   # listifies a hash: (a => 1,b => 1) -> (a,b) 
   my($hash) = @_;
   my(@list,$key);
   @list = ();
   foreach $key (keys %$hash) {
      push(@list,$key);
   }
   return \@list;
}

sub printit {
   my($listname1,$listname2,$equal) = @_;
   if ($equal) { 
      print "Same Lists: ", $listname1, " and ", $listname2, "\n"; 
   } else {
      print "Different Lists: ", $listname1, " and ", $listname2, "\n"; 
   }
}

#sub sort {} 
#sub unique {} 
#sub push_file { }

package main;

   print "\nlist1:\n";
   $list1 = StringList->new();
   $toadd = ['a','b','b','c','d','d','e','f','f'];
   $list1->push($toadd);

   $list3 = StringList->new();
   $toadd = ['d','e','f','g','h','i'];
   $list3->push($toadd);

   $size = $list1->size();
   print "size: $size\n";

   for ($i = 0; $i < $size; $i++) {
      $item = $list1->at($i);
      print "item $i: $item\n";
   }
   print "\n";

   print "list1: ", $list1->stringify(), "\n";

   $list2 = $list1->elimdups();
   print "list2: ", $list2->stringify(), "\n";

   print "list3: ", $list3->stringify(), "\n";

   StringList::printit("list1","list2",$list1->sameitems($list2));
   StringList::printit("list1","list3",$list1->sameitems($list3));


   print "\nClearing out list1:\n";
   $list1->clear();
   print "list1: ", $list1->stringify(), "\n";

   exit;

    Source: geocities.com/soho/square/Square/3472

               ( geocities.com/soho/square/Square)                   ( geocities.com/soho/square)                   ( geocities.com/soho)