Lab 7

The idea behind this lab is to develop functions that will be useful in performing random testing on your solutions to Assignment 4 and beyond.

Please note that the word "term" here means the same thing as "expression".

• Copy the definition of the AST definition from Assignment 3.

• To allow you to use the random and random-seed functions, import them like this:

  (require (typed-in racket

  [random : (number -> number)]

  [random-seed : (number -> void)]))

• Develop the function randomTerm that produces a term containing only functions of one parameter, applications with one argument, and variable references. You’ll need to devise some mechanism that produces trees of a reasonable size

• Refine your function randomClosedTerm so that it only produces "closed" CFAEs: that is, those with no free variables. To do this, your function must accept a list of currently-bound variables, so that it can be sure to pick varrefs only from this list.

• Use the randomClosedTerm function to test your interpreter. Use printf to display the term before calling interp on it. Can you find a term that loops forever? Can you generate any other errors?