Update generator syntax

d-.scm

@@ -9,7 +9,7 @@
    for
    partial
    argmin
-   make-generator))
+   generator))
 
 (define-syntax ~>
   (syntax-rules ()
@@ -67,3 +67,12 @@
       (lambda (k value)
 	(set! thunk k)
 	value))))
+
+(define-syntax generator
+  (lambda (x)
+    (syntax-case x ()
+      [(generator expr ...)
+       (with-syntax ([yield (datum->syntax x 'yield)])
+	 #'(make-generator
+	    (lambda (yield)
+	      expr ...)))])))