The Implementation of a Persistent Type-Safe Object-Oriented Programming Language

In many software development systems semantic checking is performed after the editing process and within an "edit-compile-execute" cycle. When such systems are used in a teaching role, students may construct programs, and larger-scale software systems, which contain type errors. All type errors must be corrected if the software is to execute properly and this involves a significant overhead. In the IOPL (Initial Object-Oriented Programming Language) system, incremental type checking is provided via an editor that manipulates the persistent abstract syntax representation of an application, ensuring that no syntax errors and no type errors occur during the editing process.