From 62e0073af6298dbd3c47f125e73331f2173767a8 Mon Sep 17 00:00:00 2001
From: Jack Firth <jackhfirth@gmail.com>
Date: Wed, 8 Jul 2015 10:55:06 -0700
Subject: [PATCH] Change lens-view*

---
 lens/base/view-set.rkt   | 28 +++++++++++++---------------
 lens/base/view-set.scrbl |  9 ++-------
 2 files changed, 15 insertions(+), 22 deletions(-)

diff --git a/lens/base/view-set.rkt b/lens/base/view-set.rkt
index c63424b..6db0455 100644
--- a/lens/base/view-set.rkt
+++ b/lens/base/view-set.rkt
@@ -10,31 +10,30 @@
 
 (provide
  (contract-out [lens-view (-> lens? any/c any/c)]
-               [lens-view* (->* (any/c) #:rest (listof lens?) any/c)]
+               [lens-view* (->* (any/c) #:rest (listof lens?) list?)]
                [lens-set (-> lens? any/c any/c any/c)]
                [lens-set* (->* (any/c) #:rest (listof2 lens? any/c) any/c)]))
 
 
-(define (lens-view lens v)
-  (let-lens (view _) lens v
+(define (lens-view lens target)
+  (let-lens (view _) lens target
     view))
 
-(define (lens-set lens v x)
-  (let-lens (_ setter) lens v
+(define (lens-set lens target x)
+  (let-lens (_ setter) lens target
     (setter x)))
 
-(define (lens-view* v . lenses)
-  (for/fold ([v v]) ([lens (in-list lenses)])
-    (lens-view lens v)))
+(define (lens-view* target . lenses)
+  (map (lens-view _ target) lenses))
 
-(define (lens-set* v . lenses/xs)
+(define (lens-set* target . lenses/xs)
   (unless (even? (length lenses/xs))
     (error 'lens-set*
            "expected an even number of association elements\n  association elements: ~v"
            lenses/xs))
-  (for/fold ([v v]) ([lens/x (in-slice 2 lenses/xs)])
+  (for/fold ([target target]) ([lens/x (in-slice 2 lenses/xs)])
     (match-define (list lens x) lens/x)
-    (lens-set lens v x)))
+    (lens-set lens target x)))
 
 (module+ test
   (define (set-first l v)
@@ -45,10 +44,9 @@
   (define second-lens (make-lens second set-second))
   (check-equal? (lens-view first-lens '(1 2 3)) 1)
   (check-equal? (lens-set first-lens '(1 2 3) 'a) '(a 2 3))
-  (check-equal? (lens-view* '((1 2) 3) first-lens second-lens)
-                2)
+  (check-equal? (lens-view* '(1 2 3) first-lens second-lens)
+                '(1 2))
   (check-equal? (lens-set* '(1 2 3)
                            first-lens 10
                            second-lens 20)
-                '(10 20 3))
-  )
+                '(10 20 3)))
diff --git a/lens/base/view-set.scrbl b/lens/base/view-set.scrbl
index c847089..18789f4 100644
--- a/lens/base/view-set.scrbl
+++ b/lens/base/view-set.scrbl
@@ -24,13 +24,8 @@
 ]}
 
 @defproc[(lens-view* [target target/c] [lens lens?] ...) view/c]{
-  Like @racket[lens-view], except that it can take multiple lenses,
-  which are combined into a nested lens. The argument order is
-  switched, so that the @racket[target] comes first and the
-  @racket[lens] arguments come after it.
-  @racket[(lens-view* target lens ...)] produces the same value as
-  @racket[(lens-view (lens-thrush lens ...) target)], but can be more
-  efficient.
+  Like @racket[lens-view], except that it takes multiple lenses and
+  returns a list of views.
   @lenses-examples[
     (lens-view* '(a b ((c d) e f) g) third-lens first-lens second-lens)
 ]}