<< In 1979, a pre-Infocom MIT S.W. Galley and his collaborator wrote a how-to document for the MDL programming language. Intended to be a simple overview, it expanded into a full book. Here's a Microfilm photo of this work, courtesy of the lovelies over at the ZIL Facebook group.>>
Huh, Sussman and Hewitt wrote Muddle!
Also Johnny Five and/or the WOPR probably run Muddle.
@larsbrinkhoff I can see though why they didn't use Enter - it was so you could enter an multiline expression without evaluating it. Which makes sense.
"I appreciate SDF but it's a general-purpose server and the name doesn't make it obvious that it's about art." - Eugen Rochko