package TestArray;
use Tie::Array;
use parent -norequire, 'Tie::StdArray';
use strict;
use warnings;
use Carp qw/cluck/;
$| = 1;
our %STASH;

sub TIEARRAY  { 
    my $o = bless [], $_[0];
    $STASH{$o} = { DEBUG => 0};
    return $o;
}

sub DESTROY {
    my $o = shift;
    if( $STASH{$o}{DEBUG} ) {
        cluck "Called DESTROY.";
    }
    delete $STASH{$o};
}

sub debug {
    my $self = shift;
    my $newstate = shift;
    if( defined $newstate ) {
        $STASH{$self}{DEBUG} = $newstate;
    }
    return $STASH{$self}{DEBUG};
}

sub STORE     {
    if( $STASH{$_[0]}{DEBUG} ) {
        cluck "Called STORE on element [$_[1]] with value '$_[2]'";
    }
    $_[0]->[$_[1]] = $_[2] 
}

sub POP {
    if( $STASH{$_[0]}{DEBUG} ) {
        cluck "Called POP: Returned '$_[0][-1]'.";
    }
    pop( @{$_[0]} );
}

sub SHIFT {
    if( $STASH{$_[0]}{DEBUG} ) {
        cluck "Called SHIFT: Returned '$_[0][0]'.";
    }
    shift( @{$_[0]} );
}

sub PUSH {
    local $" = "', '";
    my $o = shift;
    if( $STASH{$o}{DEBUG} ) {
        cluck "Called PUSH with args '@_'";
    }
    push( @$o, @_ );
}

sub UNSHIFT {
    local $" = "', '";
    my $o = shift;
    if( $STASH{$o}{DEBUG} ) {
        cluck "Called UNSHIFT with args '@_'";
    }
    unshift( @$o, @_ );
}

sub CLEAR {
    if( $STASH{$_[0]}{DEBUG} ) {
        cluck "Called CLEAR.";
    }
    @{$_[0]} = ();
}

sub DELETE {
    if( $STASH{$_[0]}{DEBUG} ) {
        cluck "Called DELETE with arg $_[1]";
    }
    delete $_[0]->[$_[1]];
}




package main;

use strict;
use warnings;
use v5.12;

our $o; # Tied array object.

BEGIN {
    @ARGV = ( 'A' .. 'Z' );
    my @temp = @ARGV;
    $o = tie @ARGV, 'TestArray';
    @ARGV = @temp;
    $o->debug(1);
}

say "@ARGV";

say "pop() test.";
my $test = pop( @ARGV );

say "push() test.";
push @ARGV, 'ZZ';

say "shift() test.";
$test = shift( @ARGV );

say "unshift() test.";
unshift( @ARGV, $test );

say "delete() test.";
delete( $ARGV[-1] );

say "Assignment test.";
$ARGV[0] = 'AA';

say "CLEAR() test.";
@ARGV = ();