Designers Need End-User Software Engineering

For many years I have been interested in how design works, and in how to support designers doing design. Inspired by tools like Macsyma (and later Mathematica, etc.), I became interested in building end-user languages and tools that are in a sense general-purpose systems and yet that end users can tailor or customize to correspond to their own needs. Whether there are specific structures and operations that are unique to design (across the disciplines, but distinct perhaps from other kinds of problem solving) I do not yet know, but it seems at least plausible that programming languages for design may have a special character. That question that has framed much of my work.