adding new object.h for ch.20 ex.19

.gitignore

@@ -4,3 +4,4 @@
 !Makefile
 !README.md
 !*.py
+!*.h

object.h

@@ -0,0 +1,27 @@
+#ifndef _object_h
+#define _object_h
+
+typedef enum {
+    NORTH, SOUTH, EAST, WEST
+} Direction;
+
+typedef struct {
+    char *description;
+    int (*init)(void *self);
+    void (*describe)(void *self);
+    void (*destroy)(void *self);
+    void *(*move)(void *self, Direction direction);
+    int (*attack)(void *self, int damage);
+} Object;
+
+int Object_init(void *self);
+void Object_destroy(void *self);
+void Object_describe(void *self);
+void *Object_move(void *self, Direction direction);
+int Object_attack(void *self, int damage);
+void *Object_new(size_t size, Object proto, char *description);
+
+#define NEW(T, N) Object_new(sizeof(T), T##Proto, N)
+#define _(N) proto.N
+
+#endif