usql updates, lexer changes

usql/parser.cpp

@@ -191,8 +191,10 @@ namespace usql {
 	    // column values
 	    m_lexer.skipToken(TokenType::open_paren);
 	    do {
-		    auto col_value =  parse_expression();
-		    column_values.push_back(std::move(col_value));
+		    // TODO here it is problem when exception from parse_expression<-parse_value is thrown
+		    // it makes double free
+		    auto value = parse_expression();
+		    column_values.emplace_back(std::move(value));
 
 		    m_lexer.skipTokenOptional(TokenType::comma);
 	    } while (m_lexer.tokenType() != TokenType::close_paren);
@@ -408,7 +410,6 @@ namespace usql {
 	    // parenthesised expression
 	    if (token_type == TokenType::open_paren) {
             m_lexer.skipToken(TokenType::open_paren);
-            
 		    auto left = parse_expression();
 		    do {
 			left = parse_expression(std::move(left));
@@ -450,6 +451,14 @@ namespace usql {
 	    if (token_type == TokenType::keyword_null)
 		return std::make_unique<NullValueNode>();
 
+	    // true / false
+	    if (token_type == TokenType::keyword_true || token_type == TokenType::keyword_false)
+		return std::make_unique<BooleanValueNode>(token_type == TokenType::keyword_true);
+
+	    // token * for count(*)
+	    if (token_type == TokenType::multiply)
+		    return std::make_unique<StringValueNode>(tokenString);
+
 	    throw Exception("Unknown operand node " + tokenString);
     }
 
@@ -468,6 +477,12 @@ namespace usql {
 			    return RelationalOperatorType::lesser;
 		    case TokenType::lesser_equal:
 			    return RelationalOperatorType::lesser_equal;
+		    case TokenType::is:
+		    	    if (m_lexer.tokenType() == TokenType::keyword_not) {
+					m_lexer.skipToken(TokenType::keyword_not);
+			    		return RelationalOperatorType::is_not;
+			    }
+			    return RelationalOperatorType::is;
 		    default:
 			    throw Exception("Unknown relational operator " + op.token_string);
 	    }