RosettaCodeData/Task/Balanced-brackets/M2000-Interpreter/balanced-brackets.m2000

module Balanced_brackets{
    // Generate a string with   N   opening brackets   [   and with   N   closing brackets   ],   in some arbitrary order.
    function randomBrackets(max as long) {
        if max<1 then max=1
        def putbracket()=mid$("[[[[]]",random(1,6),1)
        dim a(random(1, max)) as string<<putbracket()
        =a()#str$("")
    }
    // Determine whether the generated string is balanced; that is, whether it consists entirely of pairs of opening/closing brackets (in that order), none of which mis-nest.
    function check(s as string) {
        long i, level
        for i=1 to len(s)
        if mid$(s,i,1)="[" then level++ else level--
        if level<0 then exit for
        next
        =level=0
    }
    string k
    boolean m
    do
        k=randomBrackets(10)
        m=check(k)
        print k;@(12);":  ";if$(m->"OK", "NOT OK")
    until m
}
Balanced_brackets