Josef, the robot

Abstract

Computers cannot be properly understood without at least an elementary exposure to programming. Many teachers would reject this proposal on the grounds that for many people programming is too difficult and uninteresting. This objection is probably correct if we imply that programming should be introduced in a general purpose programming language. Its validity becomes questionable if the vehicle is a special programming language which puts the student into a natural environment, familiar to every ordinary person. The LOGO system is a well known example of such a natural environment. This article presents a related language called Josef which is used to program a robot moving on the map of a computer terminal. The distinguishing features of Josef are: (a) Extensibility of built-in vocabulary: (b) Possibility of fully top-down approach to the solution of large problems; (c) Similarity to general purpose languages in terms of concepts available in the language and the syntax used to express them: (d) Ability to work on ordinary computer terminals. The larger part of the article attempts to present the general philosophy of the language on a few programming examples of medium complexity.