Donkey provides a friendly environment in which to compose or debug a program, and Figure 1 shows how it is laid out. The Donkey window contains, from top to bottom, the menu bar (Section 4), button bar, next reduction rule area, workspace, and message area. The workspace contains blocks, each of which consist of an edit area and an evaluation area. The user may work in one of these blocks at a time; this is called the current block .