Invention involves a process for automatically producing a computer program in machine assembly language directly from a two-dimensional network representing the flow of data and control logic which it is desired to accomplish on a specified general purpose digital computer. The network used to represent the desired data processing to be programmed involves a fundamentally new type of graphical representation, herein referred to as "data flow circuits". A specially defined "vocabulary" of some 50 basic data processing "data circuit elements" constitute the building blocks of data flow circuits. These elements on the one hand are functionally equivalent to hardware digital processing operations, and on the other hand are exactly defined as a set of computer instructions. The automatic preparation of a computer program by this method is especially advantageous when used with a computer-driven graphics terminal which provides for rapid and interactive configuration of the data flow circuit, on-line testing and immediate output of the final computer program.