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_mem(Actions)
  10 {
  11  str method(talk) (anonymous self);
  12 };
  13
  14 def_mem(Animal)
  15 {
  16  interface(Actions);
  17  char *name;
  18 };
  19
  20 construct(Animal) (Animal self, str name)
  21 {
  22  self->name = name;
  23  return self;
  24 }
  25
  26 str cat_talk(anonymous self)
  27 {
  28  return "Meow!";
  29 }
  30
  31 str dog_talk(anonymous self)
  32 {
  33  return "Arf! Arf!";
  34 }
  35
  36 Actions cat_actions(void)
  37 {
  38  Get_mem(this,Actions);
  39
  40  this->talk = cat_talk;
  41  return this;
  42 }
  43
  44 Actions dog_actions(void)
  45 {
  46  Get_mem(this,Actions);
  47
  48  this->talk = dog_talk;
  49  return this;
  50 }
  51
  52 program
  53 {
  54  int i;
  55  Animal animal[3];
  56  Actions cat = cat_actions();
  57  Actions dog = dog_actions();
  58
  59  animal[0] = get_obj(Animal,cat,"Missy");
  60  animal[1] = get_obj(Animal,cat,"Mr. Bojangles");
  61  animal[2] = get_obj(Animal,dog,"Lassie");
  62
  63  for_range(i, 0, 2)
  64  {
  65   print(animal[i]->name,":",_(talk,animal[i]));
  66  }
  67 }