Shplait Lambda 4 Exp And Parse

Summary

Our third and final step in understaning the `letrec` encoding is to convert the pieces into Curly notation and identify the equivalent ... Representing `fun` forms and motivating the associated generalization of application forms. Updating `interp` to support `fun` expressions. Using `first`, `rest`, and `is_cons`. Numbers, booleans, strings, and symbols. Distinguishing expressions from values, and treating functions as values. Looking at the evaluation of `fun` forms and the representing the result as a closure. Representing function definitions and function calls