APLG-An APL based system for interactive computer graphics
Wolfgang K. Giloi, J. Encarnação · 1974
Computer Graphics (CG) is in its essence interactive. The customary "batch processing" languages such as, for example, FORTRAN, ALGOL, PL/I, ..., are not primarily designed for interactive use. One of the main reasons for that is their relatively early binding time. Another handicap, particularly for CG, is a certain inadequacy of their control structure for the kind of dialog characterizing CG. Thus, the usual programming packages for CG based on one of the above mentioned high-level languages have to be augmented by devices which allow the system to lend control to the user, together with a simple command language which enables the user to execute temporarily control over the system. The commands are given to a command language processor which works interpretatively, initiating, for instance, respective subroutine calls.