my @arr = qw( one two three );

sub while_with_shift_push {
        my $ref;
        my @cp = @arr;
        push( @$ref, $_ ) while( $_ = shift( @cp ) );
        return $ref;
}

sub for_with_push {
        my $ref;
        my @cp = @arr;
        push( @$ref, shift( @cp ) ) for ( 0..$#cp );
        return $ref;
}

sub splice_it {
        my $ref;
        my @cp = @arr;
        push( @$ref, splice( @cp ) );
        return $ref;
}

sub push_with_clear {
        my @cp = @arr;
        my $ref;
        push( @$ref, @cp );
        @cp = ();
        return $ref;
}