An initial object-oriented programming language (IOPL) and its implementation

Object-oriented programming languages designed for introductory teaching simplify the often overcomplex features of conventional languages, but usually do so within software development environments that mimic their conventional counterparts. In such systems, semantic checking is performed after the editing process and within a conventional edit-compile-execute cycle. The initial object-oriented programming language (IOPL) provides incremental semantic checking via a structure editor that manipulates the persistent abstract syntax representation of an application and ensures that no syntax errors and no type errors occur during the editing process.