public ParseTree addChild(ParseTree parseTree) {
    	ParseTree[] newChildren = new ParseTree[children.length + 1];
    	for(int i = 0; i < children.length; i++)
    		newChildren[i] = children[i];
    	newChildren[newChildren.length - 1] = parseTree;
    	children = new ParseTree[newChildren.length];
    	for(int i = 0; i < children.length; i++)
    		children[i] = newChildren[i];
        return parseTree;
    }