Add generator function

d-.scm

@@ -6,7 +6,8 @@
    if-not
    when-not
    partial
-   argmin))
+   argmin
+   make-generator))
 
 (define-syntax ~>
   (syntax-rules ()
@@ -36,3 +37,15 @@
 		min))
 	  #f
 	  vals))
+
+;; Shamelessly ripped from https://wingolog.org/archives/2013/02/25/on-generators
+(define (make-generator f)
+  (define tag (make-prompt-tag))
+  (define (thunk)
+    (f (lambda (val) (abort-to-prompt tag val))))
+  (lambda ()
+    (call-with-prompt tag
+      thunk
+      (lambda (k value)
+	(set! thunk k)
+	value))))