containers := SM.insert (!containers, name, (befor, after))
fun container name = SM.find (!containers, name)
+local
+ val pr = ref (fn () => ())
+in
+
+fun registerPre f =
+ let
+ val old = !pr
+ in
+ pr := (fn () => (old (); f ()))
+ end
+fun pre () = !pr ()
+
+end
+
+local
+ val pst = ref (fn () => ())
+in
+
+fun registerPost f =
+ let
+ val old = !pst
+ in
+ pst := (fn () => (old (); f ()))
+ end
+fun post () = !pst ()
+
+end
+
fun badArgs (name, args) =
(print ("Invalid arguments to " ^ name ^ "\n");
app (fn arg => Print.preface ("Argument: ", Print.p_exp arg)) args;
SM.empty))
| two func _ _ (_, es) = badArgs (func, es)
+
+fun oneV func (name, arg) f (evs, [e]) =
+ (case arg e of
+ NONE => badArg (func, name, e)
+ | SOME v => (f (evs, v);
+ SM.empty))
+ | oneV func _ _ (_, es) = badArgs (func, es)
+
+fun twoV func (name1, arg1, name2, arg2) f (evs, [e1, e2]) =
+ (case (arg1 e1, arg2 e2) of
+ (NONE, _) => badArg (func, name1, e1)
+ | (_, NONE) => badArg (func, name2, e2)
+ | (SOME v1, SOME v2) => (f (evs, v1, v2);
+ SM.empty))
+ | twoV func _ _ (_, es) = badArgs (func, es)
+
+
+fun env arg (evs, name) =
+ case SM.find (evs, name) of
+ NONE => raise Fail ("Unavailable environment variable " ^ name)
+ | SOME e =>
+ case arg e of
+ NONE => raise Fail ("Bad format for environment variable " ^ name)
+ | SOME v => v
+
fun type_one func arg f =
registerType (func, fn e =>
case arg e of
fun action_one name args f = registerAction (name, one name args f)
fun action_two name args f = registerAction (name, two name args f)
+fun actionV_none name f = registerAction (name, fn (env, _) => (f env; env))
+fun actionV_one name args f = registerAction (name, oneV name args f)
+fun actionV_two name args f = registerAction (name, twoV name args f)
+
+fun container_none name (f, g) = registerContainer (name, none name f, g)
fun container_one name args (f, g) = registerContainer (name, one name args f, g)
+fun containerV_one name args (f, g) = registerContainer (name, oneV name args f, g)
+
type env = SS.set * (typ * exp option) SM.map * SS.set
val empty : env = (SS.empty, SM.empty, SS.empty)