#lang racket
(require "cas-cad-e.rkt")

;;; TEST   Syntax Errors
;; The syntax errors should signal errors in terms of cas-cad-e.

; (cas-cad-e)              ; neither value expression nor case-clauses present
; (cas-cad-e 1)            ; no case-clauses present
; (cas-cad-e 1 (a-datum))  ; no list of datums
; (cas-cad-e 1 ((a-datum)))  ; missing then expression

;;; TEST   Semantics

; Test 1
(define (cas1 v)
  (cas-cad-e v
             ((1) (display "1") )
             ((2) (display "2") (break 2))
             ((3)  3)))

(cas1 1) ; ==> 2       (and prints "12")
(cas1 2) ; ==> 2       (and prints "2")
(cas1 3) ; ==> 3       (and prints nothing)
(cas1 4) ; ==> <void>  (and prints nothing)

; Test 2 tests whether break works, in a context where break is unbound.
; This tests how break works when break is bound.
; If cas-cad-e shadows the binding, then it prints 5 and evaluates to 5,
; otherwise it prints 553 and evaluates to 3. 
(let ([break display])  
  (cas-cad-e 5
             ((1) (display "1") )
             ((5) (display "5") (break 5))
             ((3) (display "3") 3)))
;=>

; Test 3 
; Test whether it is possible to bind break inside a cas-cad-e expression.
; Prints 63  evaluates to 3   
(let ([break 1])  
  (cas-cad-e 6
             ((1) (display "1") )
             ((6) (display "6") (let ((break values)) (break 6)))
             ((3) (display "3") 3)))


; Test whether it possible to use cas-cad-e in syntax generated from a macro.
(require (for-syntax "cas-cad-e.rkt"))
(define-syntax (let1 stx)
  (syntax-case stx ()
    [(_ id value-expr body)
     #'(let ((id value-expr))
         (cas-cad-e 1 ((1) (break body))))]))

(let1 x 41 (+ x 1))          ; evaluates to 42
(let1 break 42 (+ break 1))  ; evaluates to 43