;; Function To Be Tested: RATIONAL
;;
;; Source: Guy L Steele's CLTL
;; Section: 12.6 Type Conversions and Component Extractions on Numbers
;; Page: 214
;;
;; Created By:    Kelly Roach, John Park
;;
;; Creation Date: July 12,1986
;;
;; Last Update:   Jan 28, 1987 - Jim Blum - Substitued (= ...) for (eq.. ...)
;;
;; Filed As:      {ERIS}<LISPCORE>CML>TEST>12-6-RATIONAL.TEST
;;
;;
;; Syntax:        (RATIONAL NUMBER)
;;
;; Function Description:
;; Each of these functions converts any non-complex number to be a rational
;; number.  If the argument is already rational, it is returned.
;; The two functions differ in their treatment of floating-point numbers.
;; 
;; RATIONAL assumes that the floating-point number is completely accurate
;; and returns a rational number mathematically equal to the precise
;; value of the floating-point number.
;; 
;; RATIONALIZE assumes that the
;; floating-point number is accurate only to the precision of the
;; floating-point representation, and may return any rational number for
;; which the floating-point number is the best available approximation of
;; its format; in doing this it attempts to keep both numerator and
;; denominator small.
;; 
;; It is always the case that
;; 
;;     (FLOAT (RATIONAL X) X) = X
;;     
;; and
;; 
;;     (FLOAT (RATIONALIZE X) X) = X
;;     
;; That is, rationalizing a floating-point number by either method
;; and then converting it back
;; to a floating-point number of the same format produces the original number.
;; What distinguishes the two functions is that RATIONAL typically
;; has a simple, inexpensive implementation, whereas RATIONALIZE goes
;; to more trouble to produce a result that is more pleasant to view and
;; simpler for some purposes to compute with.
;; 
;; Argument(s):   NUMBER - a number
;;
;; Returns:       a number
;;

(do-test rational-test
  (and (= (rational 10) 10)
       (= (float (rational 3.1)) (/ 31 10))
       (rationalp (rational 3.1))
       (= (float (rational 3.1)) 3.1)
       (= (float (rational (/ 3 10))) (/ 3 10))
       (rationalp (rational (/ 3 10)))
       (= (rational 3E3) 3000)))

STOP