changed the implementation to call/cc

contract.rkt

@@ -12,6 +12,40 @@
 ;; define/return/contract
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
+(define-syntax define/contract/return
+  (syntax-rules ()
+    ((_ (name . formals) return (c ... last-pred) b1 ...)
+     (define/contract (name . formals)
+       (c ... last-pred)
+       (call/cc
+        (λ (ret)
+          (define/contract
+            (make-ret x)
+            (-> any/c last-pred)
+            x)
+          (define (return x)
+            (ret (make-ret x)))
+
+          b1
+          ...
+          )
+        )))
+    ((_ name last-pred value)
+     (define/contract name
+       last-pred
+       (call/cc
+        (λ (ret)
+          (define/contract
+            (make-ret x)
+            (-> any/c last-pred)
+            x)
+          (define (return x)
+            (ret (make-ret x)))
+          value))))
+    )
+  )
+
+#|
 (define-syntax def-returner
   (syntax-rules ()
     ((_ pred name)
@@ -52,3 +86,4 @@
     )
   )
 
+|#

main.rkt

@@ -1,13 +1,29 @@
 #lang racket/base
 
 (provide define/return
-         return
+         ;return
          )
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; define/return
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
+(define-syntax define/return
+  (syntax-rules ()
+    ((_ def return
+        b1 ...)
+     (define def
+       (call/cc
+        (λ (return)
+          b1
+          ...)))
+     )
+    )
+  )
+
+#|
+                
+
 (struct exn:return exn (value) #:transparent)
 
 (define-syntax raise-return
@@ -76,4 +92,4 @@
      )
     )
   )
-       
+|#