alias $heap->Push( $dna );

##</code><code>##

my $heapPush= aliasize $heap->can("Push");
$heapPush->( $heap, $dna );

##</code><code>##

my @x;

sub swap {
    my( $i, $j )= @_;
    alias @x[$i,$j]= @x[$j,$i];
}

sub exchange {
    my( $i, $j )= @_;
    alias do {
        my $t= $x[$i];
        $x[$i]= $x[$j];
        $x[$j]= $t;
    };
}

##</code><code>##

swap( 0, 1 );
exchange( 0, 1 );
swap( 0, 0 );