Racket99

This is a work-in-progress implementation of the L99 Lisp problem set using Racket, a variant of Scheme Lisp.

Features

• Unit tests using RackUnit to demonstrate correctness of the algorithms
• Racket contracts to ensure correct usage of functions

Allowed Functions

To keep true to the spirit of the challenge, only a limited subset of Lisp functions are used to implement the problems themselves (basically those which would be available in most implementations of Lisp). These include:

• +, -, *, /, =, <, >, etc.
• add1
• and
• car/cdr (and variants like cadr)
• cond
• cons
• equal?
• if
• inexact->exact
• let/let*
• list
• list?
• map
• modulo
• not
• null
• null?
• or
• remainder
• sqrt
• sub1
• truncate
• values

In addition, if an implementation for a function has been given in a previous solution, it's OK to use the built-in version for later problems. These functions include:

• append (implemented in P07-flatten-list.rkt as append-list)
• gcd (implemented in P32-greatest-common-divisor.rkt as greatest-common-divisor)
• length (implemented in P04-count-list.rkt as count-list)
• list-ref (implemented in P03-element-at.rkt as element-at)
• reverse (implemented in P04-reverse-list.rkt as reverse-list)
• split-at (implemented in P17-split.rkt as split)

Other functions are fair game for unit tests.