error. Such error handling is standard in G2 5.0. In G2 4.0, an error was described using a symbol and a text string. Object-oriented error handling supersedes this practice. If your KB is new in G2 5.0, you can ignore symbol/text error handling. If your KB already uses G2 4.0 symbol/text error handling, you can continue to use it if you prefer. The syntax is described under Superseded On Error Statement Syntax and Superseded Signal Statement Syntax.
The two types of error handling can be freely intermixed: G2 translates automatically between them, as described under Mixing Error Handling Techniques. New code should use only the object-oriented techniques described in this chapter.