Quiz #1 for CS4400 starter code

code.rkt

#lang plait

; ---------------------------
; - Problem 1: Short answer -
; ---------------------------

; --------------
; - Problem 1a -
; --------------

(define-type Exp
  [numE (n : Number)]
  [plusE (left : Exp) (right : Exp)]
  [varE (name : Symbol)]
  [let1E (var : Symbol)
         (assignment : Exp)
         (body : Exp)])

(define my-exp-subst (error 'not-implemented "implement me!"))

; --------------
; - Problem 1b -
; --------------
;; Provide hypothetical changes to the host semantics.

#| Proposed change 1:

[Describe change 1...]

|#

#| Proposed change 2:

[Describe change 2...]

|#

#| Proposed change  3:

[Describe change 3...]

|#

; --------------
; - Problem 1c -
; --------------

(define-type Pokemon
  (pre-evo (name : String) (evo : Pokemon))
  (final-evo (name : String)))

(define (evolve p)
  (error 'not-implemented "implement me!"))

; --------------
; - Problem 1d -
; --------------

#| Evaluation of (succ z):

[Evaluate (succ z)...]

|#

#| Evaluation of (succ (succ z)):

[Evaluate (succ (succ z))...]

|#

#| What do you think the pattern is?

[Answer here...]

|#

; ---------------------------
; - Problem 2: Fix the code -
; ---------------------------

#| What is wrong with the code?

[Explain here...]

|#

; Fix has-pre-evo to show the correct behavior:

(define-type-alias Pokedex (Listof Pokemon))

(define (has-pre-evo pkmn dex)
  (type-case Pokedex dex 
    [empty (error 'NoPkmn "dex is empty!!")]
    [(cons p l) (if (equal? (pre-evo-evo p) pkmn) p (has-pre-evo pkmn l))]))

; ------------------------------------
; - Problem 3: From parsing and back -
; ------------------------------------

(define-type Tree
  (leaf [val : Number])
  (node [val : Number]
        [left : Tree]
        [right : Tree]))

; --------------
; - Problem 3a -
; --------------

(define (tree-parse s)
  (error 'not-implemented "implement me!"))

; --------------
; - Problem 3b -
; --------------

(define (pretty-print-tree t)
  (error 'not-implemented "implement me!"))

; --------------
; - Problem 3c -
; --------------

(define my-sexp-1 (error 'not-implemented "implement me!"))
(define my-sexp-2 (error 'not-implemented "implement me!"))
(define my-sexp-3 (error 'not-implemented "implement me!"))

(define my-tree-1 (error 'not-implemented "implement me!"))
(define my-tree-2 (error 'not-implemented "implement me!"))
(define my-tree-3 (error 'not-implemented "implement me!"))

#| Are there test cases you can come up with that violate the above two test criteria? Why or why 
not? Briefly explain by referencing your code.

[Answer here...]

|#