Overview of a display-oriented editor for INTERLISP

DED is a display-oriented editor that was designed to add the power and convenience of display terminals to INTERLISP's teletype-oriented structure editor. DED divides the display screen into a Prettyprint Region and an Interaction Region. The Prettyprint Region gives a prettyprinted view of the structure being edited; the Interaction Region contains the interaction between the user and INTERLISP's standard editor. DEDs prettyprinter allows ellision, and the user may zoom in or out to see the expression being edited with more or less detail. There are several arrow keys which allow the user to change quite easily the locus of attention in certain structural ways, as well as a menu-like facility for common command sequences. Together, these features provide a display-facility that considerably augments INTERLISP's otherwise quite sophisticated user interface.