const Chars:[string] = ["[","]"];
func GenerateString(Amount:number=4):string{
    set Result:string = "";
    <|(*1..Amount)=>Result+=Chars[math.random(0,?Chars-1)];
    send Result;
}

func IsBalanced(String:string):boolean{
    set Pairs:number = 0;
    <|(*(0..(?String-1)))=>(String::at(_)=="[")?(Pairs<0)?=>send false,Pairs++,=>Pairs--;
    send (Opens==Closes)&(Pairs==0);
}

repeat 10 {
    set s = GenerateString(math.random(2,4)*2);
    log(`{s}: {IsBalanced(s)}`);
}