define-module : taste-of-goblins
  . #:use-module : goblins
  . #:use-module : goblins actor-lib methods
  . #:export (^cell ^greeter ^cgreeter ^borked-cgreeter
              ^car-factory ^borked-car-factory)

;; define with next argument wrapped in parentheses
;; defines a named function
define (^greeter bcom our-name)    ; constructor (outer procedure)
  lambda (your-name)               ; behavior    (inner procedure)
    format #f "Hello ~a, my name is ~a!"     ; returned implicitly
           . your-name our-name

define (^cell bcom val)
  methods            ; syntax for first-argument-symbol-based dispatch
    (get)            ; takes no arguments
      . val          ; returns current value
    (set new-val)    ; takes one argument, new-val
      bcom : ^cell bcom new-val  ; become a cell with the new value

define (^cgreeter bcom our-name)
  define times-called   ; keeps track of how many times 'greet is called
    spawn ^cell 0       ; starts count at 0
  methods
    (get-times-called)
      $ times-called 'get
    (greet your-name)
      define current-times-called
        $ times-called 'get
      ;; increase the number of times called
      $ times-called 'set
        + 1 current-times-called
      format #f "[~a] Hello ~a, my name is ~a!"
             $ times-called 'get
             . your-name our-name

define (^borked-cgreeter bcom our-name)
  define times-called
    spawn ^cell 0
  methods
    (get-times-called)
      $ times-called 'get
    (greet your-name)
      pk 'before-incr : $ times-called 'get
      ;; increase the number of times called
      $ times-called 'set
        + 1 ($ times-called 'get)
      pk 'after-incr : $ times-called 'get
      error "Yikes"
      format #f "[~a] Hello ~a, my name is ~a!"
             $ times-called 'get
             . your-name our-name

;; Create a "car factory", which makes cars branded with
;; company-name.
define (^car-factory bcom company-name)
  ;; The constructor for cars to create.
  define (^car bcom model color)
    methods                      ; methods for the ^car
      (drive)                    ; drive the car
        format #f "*Vroom vroom!*  You drive your ~a ~a ~a!"
               . color company-name model
  ;; methods for the ^car-factory instance
  methods                        ; methods for the ^car-factory
    (make-car model color)       ; create a car
      spawn ^car model color

define (^borked-car-factory bcom company-name)
  define (^car bcom model color)
    methods                      ; methods for the ^car
      (drive)                    ; drive the car
        format #f "*Vroom vroom!*  You drive your ~a ~a ~a!"
               . color company-name model
  ;; methods for the ^car-factory instance
  methods                        ; methods for the ^car-factory
    (make-car model color)       ; create a car
      error "Your car exploded on the factory floor!  Ooops!"
      spawn ^car model color