Except the original Lisp and Smalltalk environments are much more than a simple REPL.
Sometimes I wish people would learn about computing history.
Presentation from Kalman Reti about Lisp Machines, check the interactivity starting at 00:44:00 and how to introduce mouse sensitive images at 01:00:00
For me "more-than-REPL" just looks like a code visualization tool where you can jump between symbolics. Mouse sensitive images looks just like a prototype of AutoCAD
Bret Victor's work is much, much more impressive, you can change variable values and see results in realtime. In that Mario game example, you can see Mario's trajectory and adjust values to see how physical parameters affect the height and distance Mario can jump, and modify gravity ticking equation to see Mario jump & walking up-side-down.
You could do that on a Lisp Machine, too. Symbolics sold a complete interactive animation and game development system. Nintendo used it in the early years. The software later got ported.
Sometimes I wish people would learn about computing history.
Presentation from Kalman Reti about Lisp Machines, check the interactivity starting at 00:44:00 and how to introduce mouse sensitive images at 01:00:00
http://www.loper-os.org/?p=932
Xerox presentations about Smalltalk-80
http://www.youtube.com/watch?v=JLPiMl8XUKU
http://www.youtube.com/watch?v=Cn4vC80Pv6Q
http://www.youtube.com/watch?v=ODZBL80JPqw