Scheme has been considered by many to be an ideal teaching language since it naturally conforms to mathematical intuition and inductive reasoning. But there have been few tools to facilitate the learning process and few good debuggers, only interpreters that produce answers without giving any intuition to how the Scheme expressions are evaluated. Donkey fulfills this role.
Donkey (built on the powerful MzScheme dialect) is an interactive Scheme debugger and editor. It provides an easy-to-use interface for evaluating expressions and stepping forward and backwards through evaluations one step at a time or by multiple steps under user control. It provides access to lists of global and local definitions, the option to display shared structure in expression, and temporary hiding of uninteresting parts of a computation, among other features. These capabilities make Donkey an ideal environment both for learning the rules of Scheme evaluation and for debugging Scheme programs.