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_type(Animal);
  10
  11 def_mem(Actions)
  12 {
  13  str method(talk) (Animal self);
  14 };
  15
  16 def_obj(Animal)
  17 {
  18  interface(Actions);
  19  char *name;
  20 };
  21
  22 construct(Animal,Actions) (Animal self, str name)
  23 {
  24  self->name = name;
  25  return self;
  26 }
  27
  28 /* implementation of methods */
  29
  30 str catTalk(Animal self)
  31 {
  32  return "Meow!";
  33 }
  34
  35 str dogTalk(Animal self)
  36 {
  37  return "Arf! Arf!";
  38 }
  39
  40 /* registration of methods to object interface */
  41
  42 Actions catActions(void)
  43 {
  44  Get_mem(this, Actions);
  45
  46  this->talk = catTalk;
  47  return this;
  48 }
  49
  50 Actions dogActions(void)
  51 {
  52  Get_mem(this, Actions);
  53
  54  this->talk = dogTalk;
  55  return this;
  56 }
  57
  58 /* usage of objects inside C<<1 program */
  59
  60 program
  61 {
  62  int i;
  63  Animal animal[3];
  64  Actions cat = catActions();
  65  Actions dog = dogActions();
  66
  67  animal[0] = get_obj(Animal, cat, "Missy");
  68  animal[1] = get_obj(Animal, cat, "Mr. Bojangles");
  69  animal[2] = get_obj(Animal, dog, "Lassie");
  70
  71  for_range(i, 0, 2)
  72  {
  73   print(animal[i]->name, ":", _(talk, animal[i]));
  74  }
  75
  76 }