Add fibers-delay/eager

knots/promise.scm

@@ -28,6 +28,7 @@
   #:export (fibers-promise?
 
             fibers-delay
+            fibers-delay/eager
             fibers-force
             fibers-promise-reset
             fibers-promise-result-available?))
@@ -105,6 +106,20 @@
            (raise-exception res)
            (apply values res))))))
 
+
+(define (fibers-delay/eager thunk)
+  (let ((promise (fibers-delay thunk)))
+    (spawn-fiber
+     (lambda ()
+       (with-exception-handler
+           (lambda _
+             ;; Silently handle this exception
+             #f)
+         (lambda ()
+           (fibers-force promise))
+         #:unwind? #t)))
+    promise))
+
 (define (fibers-promise-reset fp)
   (atomic-box-set! (fibers-promise-values-box fp)
                    #f))