> use StringTools in
>       IsBalanced( "", "[", "]" );
>       IsBalanced( "[", "[", "]" );
>       IsBalanced( "]", "[", "]" );
>       IsBalanced( "[]", "[", "]" );
>       IsBalanced( "][", "[", "]" );
>       IsBalanced( "[][]", "[", "]" );
>       IsBalanced( "[[][]]", "[", "]" );
>       IsBalanced( "[[[]][]]]", "[", "]" );
>       s := Random( 20, "[]" );
>       IsBalanced( s, "[", "]" )
> end use;
                                  true

                                 false

                                 false

                                  true

                                 false

                                  true

                                  true

                                 false

                      s := "[[]][[[[[[[[[]][][]]"

                                 false