demos/objects/objects-wiki.c

   1 #include "cll1.h"
   2
   3 /* This is C<<1 rewrite of object polymorphism from
   4    http://en.wikipedia.org/wiki/Polymorphism_in_object-oriented_programming
   5
   6    Of course there are easier ways to do the same thing... :-)
   7    (G)2008 xChas */
   8
   9 def_interface(Animal,Actions)
  10 {
  11  str method(talk) (Animal self);
  12 };
  13
  14 def_obj(Animal)
  15 {
  16  interface(Actions);
  17  char *name;
  18 };
  19
  20 construct(Animal,Actions) (Animal self, str name)
  21 {
  22  self->name = name;
  23  return self;
  24 }
  25
  26 /* implementation of methods */
  27
  28 str catTalk(Animal self)
  29 {
  30  return "Meow!";
  31 }
  32
  33 str dogTalk(Animal self)
  34 {
  35  return "Arf! Arf!";
  36 }
  37
  38 /* registration of methods to object interface */
  39
  40 Actions catActions(void)
  41 {
  42  Get_mem(this, Actions);
  43
  44  this->talk = catTalk;
  45  return this;
  46 }
  47
  48 Actions dogActions(void)
  49 {
  50  Get_mem(this, Actions);
  51
  52  this->talk = dogTalk;
  53  return this;
  54 }
  55
  56 /* usage of objects inside C<<1 program */
  57
  58 program
  59 {
  60  int i;
  61  Animal animal[3];
  62  Actions cat = catActions();
  63  Actions dog = dogActions();
  64
  65  animal[0] = get_obj(Animal, cat, "Missy");
  66  animal[1] = get_obj(Animal, cat, "Mr. Bojangles");
  67  animal[2] = get_obj(Animal, dog, "Lassie");
  68
  69  for_range(i, 0, 2)
  70  {
  71   print(animal[i]->name, ":", _(talk, animal[i]));
  72  }
  73
  74 }