diff --git a/collects/scheme/generator.ss b/collects/scheme/generator.ss
index aa4e61f1e3..2d736fd7f7 100644
--- a/collects/scheme/generator.ss
+++ b/collects/scheme/generator.ss
@@ -7,40 +7,43 @@
 
 (provide yield lambda-generator define-generator)
 
-(define-syntax-parameter yield (lambda (stx)
-                                 (raise-syntax-error #f "yield is only bound inside a sequence generator")))
+(define-syntax-parameter yield
+  (lambda (stx)
+    (raise-syntax-error #f "yield is only bound inside a sequence generator")))
 
-;; better version of shift/reset using continuation tags
-;; also use a unique value to determine the end of the sequence instead of using #f
+;; better version of shift/reset using continuation tags also use a
+;; unique value to determine the end of the sequence instead of using #f
 (define-syntax lambda-generator
   (syntax-rules ()
     [(_ (args ...) body0 bodies ...)
      (lambda (args ...)
        (let* ([last (lambda () (void))]
-              ;; current is a function that invokes user code and produces values
-              [current (lambda ()
-                         ;; a unique tag to jump to
-                         (define tag (make-continuation-prompt-tag))
-                         ;; give the value to the sequence
-                         (define next (lambda (value)
-                                        (shift-at tag f (values value f))))
-                         (syntax-parameterize ([yield (make-rename-transformer #'next)])
-                                              (reset-at tag
-                                                        body0 bodies ...
-                                                        (values #f last)
-                                                        )))]
-              [seq (make-do-sequence (lambda ()
-                                       (values
-                                         ;; produce a value and a continuation
-                                         (lambda (i) (let-values ([(value next) (current)])
-                                                       ;; set! is ugly but can we do better?
-                                                       (set! current next)
-                                                       value))
-                                         (lambda (x) (add1 x))
-                                         0
-                                         (lambda (x) (not (eq? last current)))
-                                         (lambda (v) (not (eq? last current)))
-                                         (lambda (x v) (not (eq? last current))))))])
+              ;; current is a function that invokes user code and
+              ;; produces values
+              [current
+               (lambda ()
+                 ;; a unique tag to jump to
+                 (define tag (make-continuation-prompt-tag))
+                 ;; give the value to the sequence
+                 (define next (lambda (value)
+                                (shift-at tag f (values value f))))
+                 (syntax-parameterize ([yield (make-rename-transformer #'next)])
+                   (reset-at tag body0 bodies ... (values #f last))))]
+              [seq
+               (make-do-sequence
+                (lambda ()
+                  (values
+                   ;; produce a value and a continuation
+                   (lambda (i)
+                     (let-values ([(value next) (current)])
+                       ;; set! is ugly but can we do better?
+                       (set! current next)
+                       value))
+                   (lambda (x) (add1 x))
+                   0
+                   (lambda (x) (not (eq? last current)))
+                   (lambda (v) (not (eq? last current)))
+                   (lambda (x v) (not (eq? last current))))))])
          seq))]))
 
 (define-syntax define-generator
@@ -51,6 +54,6 @@
 #|
 ;; example
 (define-generator (blah)
-                  (for ([x (in-range 0 10)])
-                       (yield x)))
+  (for ([x (in-range 0 10)])
+    (yield x)))
 |#