Antlr4.Runtime.Tree.Trees.GetNodeText C# (CSharp) Method

        public static string GetNodeText(ITree t, IList<string> ruleNames)
        {
            if (ruleNames != null)
            {
                if (t is RuleContext)
                {
                    int ruleIndex = ((RuleContext)t).RuleIndex;
                    string ruleName = ruleNames[ruleIndex];
                    int altNumber = ((RuleContext)t).getAltNumber();
                    if ( altNumber!=Atn.ATN.INVALID_ALT_NUMBER ) {
                        return ruleName+":"+altNumber;
                    }
                    return ruleName;
                }
                else
                {
                    if (t is IErrorNode)
                    {
                        return t.ToString();
                    }
                    else
                    {
                        if (t is ITerminalNode)
                        {
                            IToken symbol = ((ITerminalNode)t).Symbol;
                            if (symbol != null)
                            {
                                string s = symbol.Text;
                                return s;
                            }
                        }
                    }
                }
            }
            // no recog for rule names
            object payload = t.Payload;
            if (payload is IToken)
            {
                return ((IToken)payload).Text;
            }
            return t.Payload.ToString();
        }