#include #include #include // Object % Object ctor { %casts return self; } % Object dtor { %casts return self; } % Object differ { %casts return self != b; } % Object puto { const struct Class * class; %casts class = classOf(self); return fprintf(fp, "%s at %p\n", class -> name, self); } % delete { if (_self) free(dtor(_self)); } % classOf { %casts return self -> class; } % sizeOf { const struct Class * class = classOf(_self); return class -> size; } % isA { if (_self) { %casts return classOf(self) == class; } return 0; } % isOf { if (_self) { const struct Class * myClass; %casts myClass = classOf(self); if (class != Object()) { while (myClass != class) if (myClass != Object()) myClass = super(myClass); else return 0; } return 1; } return 0; } static void catch (int sig) // signal handler: bad pointer { assert(sig == 0); // bad pointer, should not happen } #define isObject(p) \ ( assert(p), \ assert(((struct Object *) p) -> magic == MAGIC), p ) % cast { void (* sigsegv)(int) = signal(SIGSEGV, catch); #ifdef SIGBUS void (* sigbus)(int) = signal(SIGBUS, catch); #endif const struct Object * self = isObject(_self); const struct Class * myClass = isObject(self -> class); if (class != Object()) { isObject(class); while (myClass != class) { assert(myClass != Object()); // illegal cast myClass = myClass -> super; } } #ifdef SIGBUS signal(SIGBUS, sigbus); #endif signal(SIGSEGV, sigsegv); return (void *) self; } % respondsTo { if (tag && * tag) { const struct Class * class = classOf(_self); const struct Method * p = & class -> ctor; // first int nmeth = (sizeOf(class) - offsetof(struct Class, ctor)) / sizeof(struct Method); // # of Methods do if (p -> tag && strcmp(p -> tag, tag) == 0) return p -> method ? p -> selector : 0; while (++ p, -- nmeth); } return 0; } // Class % Class dtor { %casts fprintf(stderr, "%s: cannot destroy class\n", self -> name); return 0; } % new { struct Object * object; va_list ap; %casts assert(self -> size); object = calloc(1, self -> size); assert(object); object -> magic = MAGIC; object -> class = self; va_start(ap, _self); object = ctor(object, & ap); va_end(ap); return object; } % super { %casts return self -> super; } // initialization // _Class and _Object are statically initialized structures extern const struct Class _Object; extern const struct Class _Class; %init static const struct Class _Object = { { MAGIC, & _Class }, "Object", & _Object, sizeof(struct Object), { "", (Method) 0, (Method) Object_ctor }, { "", (Method) 0, (Method) Object_dtor }, { "differ", (Method) differ,(Method) Object_differ }, { "puto", (Method) puto, (Method) Object_puto }, }; static const struct Class _Class = { { MAGIC, & _Class }, "Class", & _Object, sizeof(struct Class), { "", (Method) 0, (Method) Class_ctor }, { "", (Method) 0, (Method) Class_dtor }, { "differ", (Method) differ,(Method) Object_differ }, { "puto", (Method) puto, (Method) Object_puto }, };
