This paper describes the graphical programming environment provided by an experimental language and interpreter. The language is truly two-dimensional, providing function boxes and oriented data paths among them. The semantics is is given in dataflow terms with boxes producing outputs when all inputs are present, as in Petri net models. Programs are built up from primitives which are function boxes for arithmetic, terminal I/O, conditioning, iterating, and performing database I/O. Recursive constructs are permitted and the natural parallelism of dataflow is enhanced by permitting data values to be lists and providing a form of data path termination which connotes “apply to all list components independently.” This yields a very natural treatment of multirecord responses to database queries.

The paper is written like a primer for the programming facility with ample examples. The text is not taxing to read and the authors attain the goal of imparting the flavor of using it to create functional programs in a graphical language.