Graphical language features in ALGOL 68

摘要

The facilities of ALGOL 68 for defining new data types and operations are used for the description and manipulation of pictures. Starting with points, polygons and strings as primitives more complex pictures may be built up with operations such as uniting of pictures, positioning, scaling, and rotation. The use of the various interactive devices is shortly discussed and a sketch of the procedure, which translates the data structure being created by a GRAPHEX68 program into a graphical assembly language, is given.