;; The first three lines of this file were inserted by DrRacket. They record metadata
;; about the language level of this file in a form that our tools can easily process.
#reader(lib "htdp-beginner-abbr-reader.ss" "lang")((modname boa-struct) (read-case-sensitive #t) (teachpacks ()) (htdp-settings #(#t constructor repeating-decimal #f #t none #f ())))
;--------------------------------
; data definition for a boa:
; (from Ian Barland and John Clements, Cal-Poly June 08
;     TeachScheme!/ReachJava workshop)

(define-struct boa (color length food))
; a boa is a 
;    (make-boa color number symbol)
; a boa has: 
;    a color that is that boa's main color,
;    a length from head to tail in meters, and
;    a food that is its favorite food

; template for a function expecting a boa parameter a-boa:

;(...	   (boa-color a-boa) ...
;	   (boa-length a-boa) ...
;	   (boa-food a-boa) ...)

; template for a function producing a boa:

; (make-boa ... ... ...)

; example boa!

(define MY-FIRST-BOA (make-boa "tan" 10 "pizza"))

(check-expect (boa-color MY-FIRST-BOA)
              "tan")
(check-expect (boa-length MY-FIRST-BOA)
              10)
(check-expect (boa-food MY-FIRST-BOA)
              "pizza")

; The scenario that has boas wants to be able to tell if a given
; boa is portable or not -- that is, if it can be carried
; in a carrier of a given size;

;----------
; signature: boa-portable?: boa number -> boolean
; purpose: expects a boa and the length of a carrier in meters,
;    and produces whether that boa could fit in a carrier of that
;    size (assuming that, for maximum comfort, the length of the
;    carrier should be at least the length of the boa)

; 3 specific examples/test cases: a true case, a false case,
;    and a boundary case

(check-expect (boa-portable? (make-boa "green" 3 "arugula")
                             4)
              true)
(check-expect (boa-portable? (make-boa "green" 3 "arugula")
                             2)
              false)
(check-expect (boa-portable? (make-boa "green" 3 "arugula")
                             3)
              true)

(define (boa-portable? a-boa carrier-length)
  (<= (boa-length a-boa) carrier-length)
)

(boa-portable? (make-boa 'green 3 'arugula)
                             4)