A tool for teaching functional programming in Scala

Current version (November 12, 2009):
What is Scala?
"Scala is a general purpose programming language designed to express common programming patterns in a concise, elegant, and type-safe way. It smoothly integrates features of object-oriented and functional languages, enabling Java and other programmers to be more productive." —
What is Escalator?
Escalator is the Educational Scala Text-and-Object Renderer. On the surface it may seem that Escalator is just a text-editor and interpreter command-line in one program, but it has a number of unique features which make it more suitable for teaching programming:
Screen Shots
A part of the Scales Project. This research was supported by NSF REU grant number CCF-0851812.