have you ever tried making a cps function that takes a closure as an argument?

src/syndicate.nim

@@ -196,29 +196,21 @@ macro during*(ds: Cap; pattern: Pattern; publishBody: untyped) =
     discard observe(activeTurn(), `ds`, `pattern`, during(`callbackSym`))
 ]#
 
-type BootProc = proc (ds: Cap)
-
-#[
-proc runActor*(name: string; bootProc: BootProc) =
-  ## Run an `Actor` to completion.
-  let actor = newActor(name)
-  let actor = bootDataspace(name, bootProc)
-  while actor.running:
-    ioqueue.run()
-
-proc runActor*(name: string; bootProc: DeprecatedBootProc) {.deprecated.} =
-  ## Run an `Actor` to completion.
-  runActor(name) do (turn: Turn, ds: Cap):
-    bootProc(ds, turn)
-]#
-
 proc wrapHandler(body: NimNode; ident: string): NimNode =
   var sym = genSym(nskProc, ident)
   quote do:
-    proc `sym`(cont: Cont): Cont {.cpsMagic.} =
+    proc `sym`() =
       `body`
-      nil
 
+macro onStop*(body: untyped) =
+  let
+    handlerDef = wrapHandler(body, "onStop")
+    handlerSym = handlerDef[0]
+  result = quote do:
+    `handlerDef`
+    addOnStopHandler(`handlerSym`)
+
+#[
 macro onStop*(body: untyped) =
   quote do:
     block:
@@ -227,3 +219,4 @@ macro onStop*(body: untyped) =
       if facet.stopped():
         `body`
         return
+]#

src/syndicate/actors.nim

@@ -28,12 +28,15 @@ type
 
   FacetState = enum fFresh, fRunning, fEnded
 
+  Callback* = proc () {.nimcall.}
+
   Facet* = ref object
     ## https://synit.org/book/glossary.html#facet
     actor: Actor
     parent: Facet
     children: seq[Facet]
     stopHandlers: HandlerDeque
+    stopCallbacks: seq[Callback]
     state: FacetState
     when traceSyndicate:
       id: FacetId
@@ -221,6 +224,9 @@ proc stop(turn; facet; reason: FacetStopReason) =
     var c = whelp runNextFacetStop()
     c.facet = facet
     complete(turn, c)
+  while facet.stopCallbacks.len > 0:
+    var cb =  facet.stopCallbacks.pop()
+    cb()
   while facet.children.len > 0:
     stop(turn, facet.children.pop(), FacetStopReason.parentStopping)
   when traceSyndicate:
@@ -335,3 +341,7 @@ proc sync*(cap: Cap) {.syndicate.} =
 proc installStopHook*(c: Cont, facet: Facet): Cont {.cpsMagic.} =
   facet.stopHandlers.add(c.fn)
   return c
+
+proc addOnStopHandler*(c: Cont; cb: Callback): Cont {.cpsMagic.} =
+  c.facet.stopCallbacks.add(cb)
+  result = c