I know about @ISA(class1 class2), so I'm not asking about that, but how to merge them seamlessly into 1 derived class.

My base class uses an array of multiple objects of same type and that's not a problem. To mix and use some shorthand: 

package File_Entry { (has 3 routines, constructor & accessors):
sub new([name,[rating]]);
filename([name])
rating([rating])
}

package File_Entries { 
    use fields qw(__entries);

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This is an array of "File_Entry's"; I consider this to be my "Base Class" even though it uses "File_Entry", it doesn't have an "ISA" relation. It supports 3 public methods & 1 "friend"ly method: 
our $pckg_vars = __PACKAGE__;
    sub new () {
        my $class=$_[0];
        my $s = {};      # base class starts/nothing
        $s->{$pckg_vars} = {};
        bless $s, ref($class) || $class;
        $s->_entries_init;
        return $s;
         }
sub ratings ([index,[rating])    #r/w accessor
sub filenames([index])           #r/o accessor
sub _add_entry(\$)               #adds entry of type File_Entry

[download]
Other classes derive mostly hierarchically: 
package Class2;
our $pckg_vars = __PACKAGE__;
sub new(){
  my $class=$_[0];
  my $s = "Base"->new(params)....
  my $s->{$pckg_vars} = {};       #'local' class var space
  bless $s,$class;
  return $s;
...}
package Class3;
our $pckg_vars => __PACKAGE__;
sub new(){
   my $class=shift;
   my $s = Class2->new(params)...
   my $s->{$pckg_vars} = {};       #class3 local vars
   bless $s,$class;
   return $s;
....}
<etc>

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At some point, I have a class with multiple inheritance.... 
{
    package Entry_Display_In_Wins;
    use strict;
    our @ISA = qw(Entry_Ordering GUI_Glue);
    use base qw(Entry_Ordering); # and GUI_Glue, but base deficient
    use    fields qw( __width __height __timer__ticked     __timer__en
+abled);
... but then I get to "new"
sub new($) ...
    my ($class,$args) = @_;
    my $s= PreviousClass->new($args);
    confess "Fatal: memory for object $pckg_vars " .
    "busy (in use by someone else).\n"
    if (defined $s->{$pckg_vars});

    $s->{$pckg_vars} = {};
    bless $s, $class;
    ...
    $s->{$pckg_vars}->{'__GUI_Glue'}= GUI_Glue->new(...);
    return $s;

[download]
My problem is when I have 2 classes I am deriving from, I also have two "new" statements -- both with "pointers" or "handles" to objects of different types.

While I can rely on perl's inheritance mechanism to search my "ISA" for methods, calling anything under "Gui_Glue" needs the "handle" associated with GUI_Glue -- not the handle I got back from "PreviousClass";

So while I can rely on further derived classes to have access to both parents (via ISA), methods in either parent will only work with the specific "handle" I got back from their "new" constructors.

It's like I need a merge function: $s=class1->new() || class2->new()

Forgive my cluelessness, but it seems that the package using multiple inheritance must manually redirect all calls *through itself*, to the right methods. So if an upper method wants "create_window" (from 2nd base class GUI_Glue), then the MIUC (Multiple-Inheritance-Using-Class) needs to have it's own "create_window', then call its parent with the appropriately stored "handle" to the 2nd base class

Is there some way to "merge" the two base classes or does Entry_Display_In_Wins need to catch calls to, and function as a "Case" or "Switch" statement for each call to the 2nd-base class? Did I explain this clearly enough? Thanks! Linda

In reply to How to do multiple inheritance? by perl-diddler

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