A Programming Language for Lindenmayer Systems

Abstract

This paper describes a different approach to facilitating the design of efficient and reliable large scale computer programs. The direction taken is toward less rather than more abstraction, and toward using the computer most efficiently as a data processing machine. This is done by expressing the program in the form of a two-dimensional network with maximum visibility to the designer, and then converting the network automatically into efficient code. The interactive graphics terminal is a most powerful aid in accomplishing this process. The principal objectives are as follows: 1. Provide a computer-independent representation of a process to be accomplished by a specified (target) computer, and automatically transforming this representation into a complete program, in the assembly language of the specified computer. 2. Design the representation so as to make highly visible the processing and flow of individual data, as well as that of control logic, in the form of a two-dimensional network, and make it understandable to engineers, scientists and computer programmers. 3. Design the representation so that it can be configured readily on an interactive computer-driven graphics terminal. 4. Design a simple but powerful set of computer-independent building blocks, called Data Circuit Elements, for representing the process to be accomplished by a computer using distinct forms to represent each class of function. 5. Enable the user to simulate the execution of the Data Flow Circuits by inputting realistic data and observing the resultant logic and data flow. 6. Facilitate the design of an efficient complex data processing system by making visible the core usage and running time of each section of the process, thus avoiding the construction of a program which exceeds the capacity of the target computer, or which uses undue core capacity and time for low-priority operations. 7. Provide a representation of a computer program which is self-documenting, in a manner clearly understandable by either an engineer or programmer, making clearly visible the interfaces among subunits, the branch points and the successive steps of handling each information input. © 1972 Association for Computing Machinery Inc. All rights reserved.