A system, named ANTICS, has been developed for producing animated fihns, fihn strips, or slides depicting the execution of LISP programs. The design, implementa~sion~ and use of ANTICS ~re discussed ttnd it is compared to existing systems. ANTICS m~W be used by entering very simple commands which produce real-time animation. The system m~Ly be "backed up" and manipulated interacLively. Adwmced commands and a seI; of graphics primii;ives are ~wtilable which permig an insia'ucLor or filmmaker Lo et:ml~r(,1 details and t. ~uld l'e~Ltures not 1)rovidcd. ANTICS may l~herefere be used as an intertmtive edueati(mtd U)(,1 or as an animatiol~ system. It is inexpensive to use: a :l-rain lihn showing t,he operal~ion of Ihe reeursive functien MEMBErt was produced for t~ total (;()st of $12.00. Tim implemen t,at.i(m is dependen ~ on specific hardware, bug the design, which is based on l:he ()rg~mizal;ion ()f the LISP EVAL function, could be used on o(;her systems.
I. PROCIR, AM ANIMATION
1.1. Introduction
A system named ANTICS has been produced which animates programs written in LISP [-1]. The system is designed for use by an instructor in a programming course, allowing him or her to make fihns which will demonstrate various features of the LISP langunge and of algorithms programmed in LISP. The instructor may control the parts of LISP which are animated and the amount of detail which is shown. Also, the system is simple and inexpensive enough to be used as an on-line interactive instructional aid.
1.2. Motivation
Teaching beginning computer science ahnost always has involved graphic tools. Flowcharts, data structures, system organization diagrams, parse trees, hardware schematics, and graphic representations of certain algorithms each have an important place in the language of computer science. β’iany computer science concepts, such as the stack, the linked list, and the array have an implicit graphic language of their own which is invariably taught in beginning courses. Other more dynamic concepts do not have well-established graphic representations, since their actions are not easy to convey with fixed images. Examples of these are