DESIGN AND IMPLEMENTATION OF AN EDITOR/INTERPRETER FOR A VISUAL LOGIC PROGRAMMING LANGUAGE

The design and implementation of a programming environment including an editor, a debugger and an interpreter engine for Lograph, a general-purpose visual logic programming language, is discussed. The rationale for user-interface design decisions is presented, the goal of which is to increase cognitive support for the creation, exploration and debugging of Lograph programs. The design of the interpreter engine allows for animation of execution in the debugger. The engine takes full advantage of an efficient implementation of Prolog, and operates on a Prolog translation of Lograph programs and queries. The translated Lograph programs are probed with instrumentation code at appropriate places so that applications of Lograph rules are reported to the visual interface of the Lograph debugger as a side er effect of the execution of a program.