parse arrays

export function ParseArrayValues(str) {
    if(str == null || str == '') throw 'String to parse cannot be null or empty';
    let result = [];
    let output = [];
    let trainyard = [];
    let value = -1;
    for (let i = 0; i < str.length; i++) {
        let exp = str[i];
        if (exp == ' ') continue;
        if (exp >= '0' && exp <= '9') {
            if (value == -1) value = 0;
            value = value * 10 + parseInt(exp.toString());
            continue;
        }
        else if (value != -1) {
            output.push(value);
            value = -1;
        }
        if (exp == ',') continue;
        switch (exp) {
            case '-':
            case '[':
                output.push(exp);
                break;
            case ']':
                while (trainyard.length > 0) {
                    let c = trainyard.pop();
                    if (c == '[') break;
                    output.push(c);
                }
                output.push(exp);
                break;
            default:
                if (!(exp >= '0' && exp <= '9')) {
                    throw 'unexpected token ' + exp;
                }
                break;
        }
    }
    if (value != -1) {
        output.push(value);
        value = -1;
    }
    while (trainyard.length > 0) {
        output.push(trainyard.pop());
    }
    var arrayStack = [];
    var curArray = [];
    while (output.length > 0) {
        let exp = output.shift();
        switch (exp) {
            case '-':
                var v = -output.shift();
                curArray.push(v);
                break;
            case '[':
                arrayStack.push(curArray);
                curArray = [];
                break;
            case ']':
                var t = arrayStack.pop();
                t.push(curArray);
                curArray = t;
                break;
            default:
                curArray.push(exp);
                break;
        }
    }
    ns.print(curArray[0]);
    return curArray[0];
}