From 8cf13a9bbf84c9f63d33386ef1471084711f0c4a Mon Sep 17 00:00:00 2001
From: Sam Caldwell <samc@ccs.neu.edu>
Date: Tue, 21 May 2019 17:22:53 -0400
Subject: [PATCH] stop-when derived form

---
 racket/typed/roles.rkt | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/racket/typed/roles.rkt b/racket/typed/roles.rkt
index c655938..b2a6b51 100644
--- a/racket/typed/roles.rkt
+++ b/racket/typed/roles.rkt
@@ -22,6 +22,7 @@
          define/query-value
          define/query-set
          define/query-hash
+         stop-when
          ;; endpoints
          assert on field
          ;; expressions
@@ -338,6 +339,17 @@
             (on (retracted p)
                 (set! x (hash-remove (ref x) e-key))))])
 
+(define-typed-syntax (stop-when E script ...) ≫
+  [[forged-name ≫ _ : FacetName] ⊢ forged-name ≫ forged-name-]
+  #:with forged-name (attach #'(#%app- syndicate:current-facet-id)
+                             ':
+                             (type-eval #'FacetName))
+  ----------------------------------------
+  [≻ (on E
+         (let ([x forged-name])
+           (stop x
+                 script ...)))])
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Expressions
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;