C/sup 2/: a mixed textual/graphical environment for C

A visual programming environment for a subset of the C language is described. The C/sup 2/ environment, as it is called, runs on a personal workstation with high-resolution graphics display. Both conventional textual code entry and editing, and program composition by means of an experimental hybrid textual graphical method, are supported and coexist side by side on the screen at all times. The built-in text editor incorporates selected Unix VI commands in conjunction with a C syntax interpreter. Hybrid textual/graphical program composition is facilitated by a BLOX-type environment in which graphical icons represent program structures and text in the icons represents user-supplied parameters attached to those structures. The two representations are coupled, so that modifications entered using either one automatically generate the appropriate update in the other. Although not all of the C language is yet supported. C/sup 2/ is not a toy system. Textual files that contain C programs serve as input and output. Graphical representations serve merely as internally generated aids to the programmers and are not stored between runs.<>