Merge pull request #256 from jackfirth/255-lens-zoom-examples

Clarify zoom lens examples

unstable/lens/zoom.scrbl

@@ -15,27 +15,20 @@ is equivalent to:
 @racketblock[(lens-transform zoom-lens target (λ (v) (lens-view transform-lens v)))]
 
 @lens-unstable-examples[
-  (define first-sym->str
-    (lens-zoom first-lens symbol->string-lens))
-  (lens-view first-sym->str '(a b c))
-  (lens-set first-sym->str '(a b c) '("a" b c))
-  (lens-set first-sym->str '(a b c) '("z" b c))
-  (lens-set first-sym->str '(a b c) '("z" bee sea))
-  (lens-view first-sym->str (lens-set first-sym->str '(a b c) '("z" bee sea)))
+  (define first-zoom-second-lens
+    (lens-zoom first-lens second-lens))
+  (lens-view first-zoom-second-lens '((1 2 3) b c))
+  (lens-set first-zoom-second-lens '((1 2 3) b c) '(2000 b FOO))
 ]}
 
 @defproc[(lens-zoom* [zoom-lens lens?] [transform-lens lens?] ... ...) lens?]{
 A multi-arg version of @racket[lens-zoom], analogous to
 @racket[lens-transform/list]. It is equivalent to
 @racket[(lens-thrush (lens-zoom zoom-lens transform-lens) ...)].
 @lens-unstable-examples[
-  (define first-sym->str/second-num->str
-    (lens-zoom* first-lens symbol->string-lens second-lens number->string-lens))
-  (lens-view first-sym->str/second-num->str '(a 2 c))
-  (lens-set first-sym->str/second-num->str '(a 2 c) '("a" "2" c))
-  (lens-set first-sym->str/second-num->str '(a 2 c) '("z" "3" c))
-  (lens-set first-sym->str/second-num->str '(a 2 c) '("z" "3" sea))
-  (lens-view first-sym->str/second-num->str
-             (lens-set first-sym->str/second-num->str '(a 2 c) '("z" "3" sea)))
+  (define first-zoom-second/third-zoom-first-lens
+    (lens-zoom* first-lens second-lens
+                third-lens first-lens))
+  (lens-view first-zoom-second/third-zoom-first-lens '((1 2 3) foo (a b c)))
+  (lens-set first-zoom-second/third-zoom-first-lens '((1 2 3) foo (a b c)) '(200 FOO asdf))
 ]}
-