import system'routines;
import extensions;
import extensions'text;

randomBrackets(len)
{
    if (0 == len)
    {
        ^emptyString
    }
    else
    {
        var brackets :=
            Array.allocate(len).populate:(i => $91)
            +
            Array.allocate(len).populate:(i => $93);

        brackets := brackets.randomize(len * 2);

        ^ brackets.summarize(new StringWriter()).toString()
    }
}

extension op
{
    get isBalanced()
    {
        var counter := new Integer(0);

        self.seekEach:(ch => counter.append((ch==$91).iif(1,-1)) < 0);

        ^ (0 == counter)
    }
}

public program()
{
    for(int len := 0, len < 9, len += 1)
    {
        var str := randomBrackets(len);

        console.printLine("""",str,"""",str.isBalanced ? " is balanced" : " is not balanced")
    };

    console.readChar()
}