oop: special methods to handle missing slots.

* struct.h (slotset_s, static_slot_s, static_slot_set_s): New
symbol variables declared.
(enum special_slot): New enum symbols: slot_m, slotset_m,
static_slot_m, static_slot_set_m.

* struct.c (slotset_s, static_slot_s, static_slot_set_s): New
symbol variables.
(special_sym): Associate new symbols with new enums.
(struct_init): Intern slotset, static-slot and static-slot-set
symbols, initializing the variables. Change the registrations
of the same-named functions to use the variables.
(slot, maybe_slot, slotset, static_slot, static_slot_set):
In the no-such-slot case, check for the special method and
call it.

* tests/012/oop.tl: New tests.

* txr.1: Documented.

1 files changed, 2 insertions, 2 deletions

diff --git a/struct.h b/struct.h
index 0b284ac0..e3d75221 100644
--- a/struct.h
+++ b/struct.h
@@ -28,7 +28,7 @@
 
 extern val struct_type_s, meth_s, print_s, make_struct_lit_s;
 extern val init_k, postinit_k;
-extern val slot_s, derived_s;
+extern val slot_s, slotset_s, static_slot_s, static_slot_set_s, derived_s;
 extern val lambda_set_s;
 extern val iter_begin_s, iter_more_s, iter_item_s, iter_step_s, iter_reset_s;
 
@@ -39,7 +39,7 @@ enum special_slot {
   equal_m, copy_m, nullify_m, from_list_m, lambda_m, lambda_set_m,
   length_m, length_lt_m, car_m, cdr_m, rplaca_m, rplacd_m,
   iter_begin_m, iter_more_m, iter_item_m, iter_step_m, iter_reset_m,
-  plus_m,
+  plus_m, slot_m, slotset_m, static_slot_m, static_slot_set_m,
   num_special_slots
 };