ProgrammingLanguageNr1.Parser.operand C# (CSharp) Method

        private AST operand()
        {
            #if WRITE_DEBUG_INFO
            Console.WriteLine("operand");
            #endif

            AST operandTree = null;

            if (lookAheadType(1) == Token.TokenType.NAME &&
                lookAheadType(2) == Token.TokenType.PARANTHESIS_LEFT)
            {
                operandTree = functionCall();
            }
            else if ( 	lookAheadType(1) == Token.TokenType.NAME &&
                 		lookAheadType(2) == Token.TokenType.BRACKET_LEFT )
            {
                operandTree = arrayLookup();
            }
            else if ( lookAheadType(1) == Token.TokenType.FROM )
            {
                operandTree = fromMinToMaxArrayCreation();
            }
            else if (lookAheadType(1) == Token.TokenType.NAME)
            {
                Token operandToken = match(Token.TokenType.NAME);
                operandTree = new AST(operandToken);
            }
            else if (lookAheadType(1) == Token.TokenType.NUMBER)
            {
                Token operandToken = match(Token.TokenType.NUMBER);

                float number = (float)Convert.ToDouble(operandToken.getTokenString(),
                                                       CultureInfo.InvariantCulture
                                                       );

                operandTree = new AST(new TokenWithValue(operandToken.getTokenType(),
                                                         operandToken.getTokenString(),
                                                         number));
            }
            else if (lookAheadType(1) == Token.TokenType.QUOTED_STRING)
            {
                Token operandToken = match(Token.TokenType.QUOTED_STRING);
                operandTree = new AST(new TokenWithValue(operandToken.getTokenType(),
                                                         operandToken.getTokenString(),
                                                         operandToken.getTokenString()));
            }
            else if (lookAheadType(1) == Token.TokenType.BOOLEAN_VALUE)
            {
                Token operandToken = match(Token.TokenType.BOOLEAN_VALUE);
                bool boolean = operandToken.getTokenString().ToLower() == "true" ? true : false;
                operandTree = new AST(new TokenWithValue(operandToken.getTokenType(),
                                                         operandToken.getTokenString(),
                                                         boolean));
            }
            else if (lookAheadType(1) == Token.TokenType.OPERATOR &&
                     lookAhead(1).getTokenString() == "-")
            {
                operandTree = negativeExpression();
            }
            else if (lookAheadType(1) == Token.TokenType.OPERATOR &&
                     lookAhead(1).getTokenString() == "+")
            {
                match(Token.TokenType.OPERATOR); // discard
                operandTree = operand();
            }
            else if (lookAheadType(1) == Token.TokenType.BRACKET_LEFT)
            {
                operandTree = arrayCreation();
            }

            return operandTree;
        }