Having a REPL in scratch means you can interactively tweak things.
IELM is more of a proper REPL, however.
Re:Goodbye Basecamp, This Is The End
by ZackOfAllTrades on Monday June 27, 2011 @10:32AM
(#2701409)
Keywiz made me realize I know absolutely nothing about emacs.
* Scripts such as keywiz let you incrementally improve your knowledge.
* Having a REPL in scratch means you can interactively tweak things.