diff -urN v22/mem.c v23/mem.c
--- v22/mem.c	2018-09-14 21:50:19.000000000 +0900
+++ v23/mem.c	2018-09-14 21:53:22.000000000 +0900
@@ -78,6 +78,40 @@
 	free(p);
 }
 
+struct callback{
+	struct callback *prev, *next;
+
+	const char *func;
+	void (*f)(void *p);
+};
+
+static struct callback *top_cb = NULL;
+
+void
+mem_add_callback(const char *func, void (*f)(void *p))
+{
+	struct callback *cb = malloc( sizeof(*cb) );
+	cb->func = func;
+	cb->f = f;
+	top_cb = chain_add_tail(top_cb, cb);
+}
+
+static void
+call_cb(struct node *nd)
+{
+	struct callback *cb = top_cb;
+
+	while(cb){
+		if( strcmp(cb->func, nd->func) == 0 ){
+			break;
+		}
+		cb = cb->next == top_cb ? NULL : cb->next;
+	}
+	if(cb){
+		(*cb->f)(nd->p);
+	}
+}
+
 void
 mem_show(void)
 {
@@ -87,6 +121,9 @@
 	while(nd){
 		fprintf(stderr, "%p %d %s %s %d %s()\n", 
 			nd->p, nd->sz, nd->kind, nd->filename, nd->line, nd->func);
+
+		call_cb(nd);
+
 		nd = nd->next == top ? NULL : nd->next;
 	}
 	fprintf(stderr, "\n");
diff -urN v22/mem.h v23/mem.h
--- v22/mem.h	2018-09-14 21:50:19.000000000 +0900
+++ v23/mem.h	2018-09-14 21:53:22.000000000 +0900
@@ -6,6 +6,7 @@
 char *mem_strndup(const char *s, int n, const char *filename, int line, const char *func);
 void mem_free(void *p, const char *filename, int line, const char *func);
 
+void mem_add_callback(const char *func, void (*f)(void *p));
 void mem_show(void);
 
 #ifdef MEM_DBG
@@ -15,6 +16,7 @@
 #define free(p)		mem_free(p, __FILE__, __LINE__, __func__)
 #else
 #define mem_show()
+#define mem_add_callback(func, f)
 #endif
 
 #endif
diff -urN v22/objs.c v23/objs.c
--- v22/objs.c	2018-09-14 21:50:19.000000000 +0900
+++ v23/objs.c	2018-09-14 21:53:22.000000000 +0900
@@ -98,11 +98,85 @@
 	}
 }
 
+#ifdef MEM_DBG
+
+static char *
+typ_name(int typ)
+{
+	struct{
+		int typ;
+		char *name;
+	} lst[]= {
+		{ OBJ_TYP_INT,		"int" },
+		{ OBJ_TYP_DOUBLE,	"double" },
+		{ OBJ_TYP_PTR,		"ptr" },
+		{ OBJ_TYP_OBJS,		"objs" },
+		{ OBJ_TYP_BOOL,		"bool" },
+		{ OBJ_TYP_LIST,		"list" },
+		{ OBJ_TYP_DICT,		"dict" },
+		{ OBJ_TYP_STR,		"str" },
+		{ OBJ_TYP_BUF, 		"buf" },
+	};
+	int n = sizeof(lst) / sizeof(*lst), i;
+
+	for(i=0; i<n; i++){
+		if(lst[i].typ == typ){
+			break;
+		}
+	}
+	return i < n ? lst[i].name : "?";
+}
+
+static void
+dbg_obj_new(void *p)
+{
+	struct obj *obj = p;
+
+	fprintf( stderr, "typ=%s ", typ_name(obj->typ) );
+
+	switch(obj->typ){
+	case OBJ_TYP_INT:
+		fprintf( stderr, "i=%d\n", obj->any.i );
+		break;
+	case OBJ_TYP_BOOL:
+		fprintf( stderr, "bool=%s\n", obj->any.i ? "True" : "False" );
+		break;
+	case OBJ_TYP_DOUBLE:
+		fprintf( stderr, "d=%g\n", obj->any.d );
+		break;
+
+	case OBJ_TYP_PTR:
+		fprintf( stderr, "p=%p\n", obj_ptr(obj) );
+		break;
+	case OBJ_TYP_STR:
+		fprintf( stderr, "str='%s'\n", obj_ptr(obj) ? (char *) obj_ptr(obj) : "(NULL)" );
+		break;
+	case OBJ_TYP_BUF:
+		fprintf( stderr, "p=%p sz=%d n=%d\n", obj_ptr(obj), obj->sz, obj->n );
+		break;
+	}
+
+	if( OBJ_TYP_BASE(obj->typ) == OBJ_TYP_OBJS ){
+		fprintf( stderr, "objs.n=%d\n", obj->any.objs.n );
+	}
+}
+
+#endif
+
 struct obj *
 obj_new(int typ, void *vp)
 {
 	struct obj *obj = malloc( sizeof(*obj) );
+
+#ifdef MEM_DBG
+	static int done = 0;
+	if(!done){
+		mem_add_callback(__func__, dbg_obj_new);
+		done++;
+	}
+#endif
 	obj_init(obj, typ, vp);
+
 	return obj;
 }