;;;;;;;;;;;;;;;;; chapter 4 ;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;; Type Checking ;;;;;;;;;;;;;;;;;;;;;

(load "4-2.scm")

;; literal numbers and booleans pass
(type-check "1")
(type-check "true")

;; unbound variables do not pass
(type-check "x")

;; primitive expressions on right number/type of args pass
(type-check "+(2,3)")
(type-check "add1(0)")
(type-check "zero?(5)")

;; wrong number/type of arguments do not pass
(type-check "+(2,true)")
(type-check "+(1,2,3)")

;; conditionals with boolean test exp and same then/else exp types pass
(type-check "if zero?(5) then 4 else 5")
(type-check "if if zero?(5) then false else true then 1 else 2")

;; wrong test or different types in then/else exps do not pass
(type-check "if 0 then 4 else 5")
(type-check "if zero?(5) then 4 else true")

;; well-formed procedures pass
(type-check "proc(int x) x")
(type-check "proc(int x, bool y) x")
(type-check "proc(int x, bool y) y")
(type-check "proc(int x, bool y) if y then x else add1(x)")
; curry
(type-check "proc((int * int -> int) f) proc(int x) proc(int y) (f x y)")

;; ill-formed procedures do not pass
(type-check "proc((int * int -> int) f) proc(int x) proc(int y) (f x)")
(type-check "proc(int x, bool y) if x then y else add1(x)")

;; procedure applications with right argument types/number pass
(type-check
  "(proc(int x, int y) -(x,y)  4 3)"
)

;; procedure applications with wrong argument types/number do not pass
(type-check
  "(proc(int x, int y) -(x,y)  4 true)"
)

(type-check
  "(proc(int x, int y) -(x,y)  4 5 6)"
)