From 96124baec0786a2b02543a4a8b36fbe60201dbd0 Mon Sep 17 00:00:00 2001
From: Jack Firth <jackhfirth@gmail.com>
Date: Fri, 10 Jul 2015 18:55:00 -0700
Subject: [PATCH] Add lens-set-all and docs

---
 unstable/lens/main.rkt       |  6 ++++--
 unstable/lens/main.scrbl     |  1 +
 unstable/lens/view-set.rkt   | 19 +++++++++++++++++++
 unstable/lens/view-set.scrbl | 15 +++++++++++++++
 4 files changed, 39 insertions(+), 2 deletions(-)
 create mode 100644 unstable/lens/view-set.rkt
 create mode 100644 unstable/lens/view-set.scrbl

diff --git a/unstable/lens/main.rkt b/unstable/lens/main.rkt
index 70d8cf1..b657015 100644
--- a/unstable/lens/main.rkt
+++ b/unstable/lens/main.rkt
@@ -3,9 +3,11 @@
 (require "syntax.rkt"
          "compound.rkt"
          "list.rkt"
-         "hash.rkt")
+         "hash.rkt"
+         "view-set.rkt")
 
 (provide (all-from-out "syntax.rkt"
                        "compound.rkt"
                        "list.rkt"
-                       "hash.rkt"))
+                       "hash.rkt"
+                       "view-set.rkt"))
diff --git a/unstable/lens/main.scrbl b/unstable/lens/main.scrbl
index 665bb09..90299a2 100644
--- a/unstable/lens/main.scrbl
+++ b/unstable/lens/main.scrbl
@@ -9,6 +9,7 @@ This library provides additional features for the
 may change in future releases. Do not depend on
 this library being backwards-compatible.
 
+@include-section["view-set.scrbl"]
 @include-section["compound.scrbl"]
 @include-section["list.scrbl"]
 @include-section["hash.scrbl"]
diff --git a/unstable/lens/view-set.rkt b/unstable/lens/view-set.rkt
new file mode 100644
index 0000000..e0c1519
--- /dev/null
+++ b/unstable/lens/view-set.rkt
@@ -0,0 +1,19 @@
+#lang racket
+
+(require lens
+         fancy-app)
+
+(module+ test
+  (require rackunit))
+
+(provide
+ (contract-out
+  [lens-set-all (->* (any/c any/c) #:rest (listof lens?) any/c)]))
+
+
+(define (lens-set-all target new-view . lenses)
+  (foldl (lens-set _ _ new-view) target lenses))
+
+(module+ test
+  (check-equal? (lens-set-all '(1 2 3 4 5) 'a first-lens third-lens fourth-lens)
+                '(a 2 a a 5)))
diff --git a/unstable/lens/view-set.scrbl b/unstable/lens/view-set.scrbl
new file mode 100644
index 0000000..7164099
--- /dev/null
+++ b/unstable/lens/view-set.scrbl
@@ -0,0 +1,15 @@
+#lang scribble/manual
+
+@(require lens/doc-util/main)
+
+
+@title{More Viewing and Setting}
+
+@defproc[(lens-set-all [target any/c] [new-view any/c] [lens lens?] ...) any/c]{
+  Sets the view of @racket[target] through each @racket[lens] to @racket[new--view]
+  @lenses-unstable-examples[
+    (lens-set-all '(1 2 3 4 5) 'a
+                  first-lens
+                  third-lens
+                  fourth-lens)
+]}