Exemplo n.º 1
0
 /// <summary>
 /// Peek at the next available token without consuming it.
 /// </summary>
 /// <returns>the next available token, or the empty token if all tokens have been read</returns>
 /// <see cref="Token.Empty"/>
 public Token PeekToken()
 {
     if (_needToken)
     {
         _nextToken = ReadTokenFromReader();
         _needToken = false;
     }
     return _nextToken;
 }
Exemplo n.º 2
0
        /// <summary>
        /// Handler for 1 or more construct
        /// </summary>
        /// <param name="separator">the separator token between items</param>
        /// <param name="terminal">the ending token</param>
        /// <param name="meth">the method to call to parse an item</param>
        /// <param name="result">the parsed expression</param>
        /// <param name="first">flag indicating whether this is the first item</param>
        /// <returns>true if match parsed, false otherwise</returns>
        private bool ReadAhead(Token separator, Token terminal, ExpressionMethod meth, out Expression result, ref bool first)
        {
            Token tok = PeekToken();
            result = null;
            if (tok == terminal)
            {
                ReadToken();
                return false;
            }
            if (!first)
            {
                RequireToken(separator, tok, "Items should be separated by {0}", separator);
                ReadToken();
            }
            else if (first && tok == separator)
                throw new ParseException(string.Format("Error: unexpected token {0} at Line: {1}, Position: {2}", tok, tok.linenumber, tok.position));

            result = meth();
            first = false;
            return true;
        }
Exemplo n.º 3
0
 /// <summary>
 /// Asserts that the token read is the one expected
 /// </summary>
 /// <param name="expected">the expected token</param>
 /// <param name="actual">the actual token</param>
 /// <param name="message">message to use in the exception if expected != actual</param>
 private static void RequireToken(Token expected, Token actual, string message, params object[] args)
 {
     if (actual != expected)
     {
         message = string.Format(message, args);
         throw new ParseException(message + " at Line: " + actual.linenumber + ", Position: " + actual.position + " Expected: " + expected + " got: " + actual);
     }
 }
Exemplo n.º 4
0
 /// <summary>
 /// Test the token to see if its a quoted string
 /// </summary>
 /// <param name="tok">the token to test</param>
 /// <returns>true if its a quoted string</returns>
 private static bool IsQuotedString(Token tok)
 {
     return tok.type == TokenType.DoubleQuotedString || tok.type == TokenType.SingleQuotedString;
 }
Exemplo n.º 5
0
 /// <summary>
 /// Test the token to see if its a keyword
 /// </summary>
 /// <param name="tok">the token to test</param>
 /// <returns>true if its a keyword</returns>
 private static bool IsKeyword(Token tok)
 {
     // include null?
     return tok.type == TokenType.Identifier && tok.value == "new";
 }
Exemplo n.º 6
0
 /// <summary>
 /// Test the token to see if its an identifier
 /// </summary>
 /// <param name="tok">the token to test</param>
 /// <returns>true if its an identifier</returns>
 private static bool IsIdentifier(Token tok)
 {
     return tok.type == TokenType.Identifier;
 }
Exemplo n.º 7
0
 private bool Equals(Token other)
 {
     return type == other.type && value == other.value;
 }