I'd welcome seeing your demo example code, when it's ready, Bob.
Jeff, I think any example program showing how to build a GUI using AppGraphics, with menus, prompts, data entry fields, a little bit of vector graphics, and callback routines triggered as necessary (eg for data entry validation as well as to invoke the main program - rather like Clive Page did using Dislin - would really light up the Fortran world.
Bob, Jeff, and others, I believe from my own experience that people with many years of coding in Fortran for prompted text-screen and/or data file i/o, who are accustomed to linear program structure, can find CallBacks and the kind of loopy/recursive program structure a bit bewildering, and having an example is a huge help in making the transition form the 1970s to the 21st century!
If I only had time, I'd love to try to create an interesting example GUI, but I have too too much work on at the moment.
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J.