#!/usr/bin/perl -w

use strict;

BEGIN{
    my %array_copy = (); # Storage of pristine arrays

    sub elements(\@;$){
        my $no_gc = $_[0]; # Hold onto $_[0] so it doesn't get garbage collected .
        my @t =  @{$_[0]}; # Temp array as I can't get it to assign to $array_copy directly.
                           # ie  $array_copy {$_[0]} = [ @{$_[0]} ]
                           # Am I missing something?

        $array_copy {$_[0]} = [@t] unless defined $array_copy{$_[0]}; # Store if we haven't.

        my @temp = @{$array_copy {$_[0]}};

        $_[1] = 1 unless $_[1] ;                    # Get one element if non specified.

        my @vals = splice(@{$_[0]}, 0, $_[1] );     # Pop elements.

        if (@vals){                                 # If elements to return
            return @vals;                           # then return them.
        }else{
            # Time to restore array back to it's previous self.

            # Tried @$_[0] = @{$array_copy {$_[0]}} but wouldn't work.
            # Seemed to temporarily change the reference, only for this statement.
            @$no_gc  = @{$array_copy {$_[0]}};  # Array now restored.
            delete $array_copy{$_[0]};          # Free array copy
            return ;                            
        }

    }

    
}

# The following is a silly example but it shows that calls to elements can be 
# nested. Also, passing an element count is optional, it will default to 1 element

my @array1 = (1..15);
my @array2 = (1..5);
print "\@array1",join(", ", @array1),"\n";
print "\@array2",join(", ", @array2),"\n\n";

while (my @v = elements(@array1,3)){
        print join(", ", @v),"\n";
        print "-" x 30,"\n";

        # Removal of elements from @array are visible here.
        while (my @x = elements(@array2,@array1) ){ # As this demonstrates.
            print "\t",join(", ", @x),"\n";
            print "\t","_" x 30,"\n";

        }
    
}

print "\@array1",join(", ", @array1),"\n";
print "\@array2",join(", ", @array2),"\n";