NeWS wasn't based on DPS. It's a full display server based on the PostScript Red Book with some extensions (canvases, lightweight processes and sync primitives, events, classes, garbage collection). This allows to write applications in this extended PostScript or in other programming languages, using a preprocessor, such as cps for C or lps for Scheme-48 and Allegro LISP, that generates PS snippets that get sent to the server.