procedures-with-setters implemented in terms of structs

[bpt/guile.git] / libguile / procs.h

diff --git a/libguile/procs.h b/libguile/procs.h
index cb19e4c..a832cd0 100644 (file)
--- a/libguile/procs.h
+++ b/libguile/procs.h
@@ -47,59 +47,6 @@
 
 
 \f
-/* Procedure-with-setter
-
-   Four representations for procedure-with-setters were
-   considered before selecting this one:
-
-   1. A closure where the CODE and ENV slots are used to represent
-   the getter and a new SETTER slot is used for the setter.  The
-   original getter is stored as a `getter' procedure property.  For
-   closure getters, the CODE and ENV slots contains a copy of the
-   getter's CODE and ENV slots.  For subr getters, the CODE contains
-   a call to the subr.
-
-   2. A compiled closure with a call to the getter in the cclo
-   procedure.  The getter and setter are stored in slots 1 and 2.
-
-   3. An entity (i.e. a struct with an associated procedure) with a
-   call to the getter in the entity procedure and the setter stored
-   in slot 0.  The original getter is stored in slot 1.
-
-   4. A new primitive procedure type supported in the evaluator.  The
-   getter and setter are stored in a GETTER and SETTER slot.  A call
-   to this procedure type results in a retrieval of the getter and a
-   jump back to the correct eval dispatcher.
-
-   Representation 4 was selected because of efficiency and
-   simplicity.
-
-   Rep 1 has the advantage that there is zero penalty for closure
-   getters, but primitive getters will get considerable overhead
-   because the procedure-with-getter will be a closure which calls
-   the getter.
-
-   Rep 3 has the advantage that a GOOPS accessor can be a subclass of
-   <procedure-with-setter>, but together with rep 2 it suffers from a
-   three level dispatch for non-GOOPS getters:
-
-     cclo/struct --> dispatch proc --> getter
-
-   This is because the dispatch procedure must take an extra initial
-   argument (cclo for rep 2, struct for rep 3).
-
-   Rep 4 has the single disadvantage that it uses up one tc7 type
-   code, but the plan for uniform vectors will very likely free tc7
-   codes, so this is probably no big problem.  Also note that the
-   GETTER and SETTER slots can live directly on the heap, using the
-   new four-word cells.  */
-
-#define SCM_PROCEDURE_WITH_SETTER_P(obj) (!SCM_IMP(obj) && (SCM_TYP7 (obj) == scm_tc7_pws))
-#define SCM_PROCEDURE(obj) SCM_CELL_OBJECT_1 (obj)
-#define SCM_SETTER(obj) SCM_CELL_OBJECT_2 (obj)
-
-
-\f
 
 SCM_API SCM scm_c_make_subr (const char *name, long type, SCM (*fcn)());
 SCM_API SCM scm_c_make_subr_with_generic (const char *name, long type,