Merge pull request #94 from jackfirth/feature-hash-list-lenses-#81

Add ref nested list and hash lenses

info.rkt

@@ -3,7 +3,7 @@
 (define collection 'multi)
 
 
-(define version "1.0")
+(define version "1.1")
 
 
 (define deps

lens/list/list-ref-take-drop.rkt

@@ -3,7 +3,6 @@
 (provide
  (contract-out
   [list-ref-lens (-> exact-nonnegative-integer? lens?)]
-  [list-ref-nested-lens (->* () #:rest (listof exact-nonnegative-integer?) lens?)]
   [take-lens (-> exact-nonnegative-integer? lens?)]
   [drop-lens (-> exact-nonnegative-integer? lens?)]
   [first-lens lens?]
@@ -61,9 +60,6 @@
 (define (list-ref-lens i)
   (lens-compose car-lens (drop-lens i)))
 
-(define (list-ref-nested-lens . args)
-  (apply lens-thrush (map list-ref-lens args)))
-
 (define first-lens (list-ref-lens 0))
 (define second-lens (list-ref-lens 1))
 (define third-lens (list-ref-lens 2))
@@ -86,6 +82,4 @@
   (check-equal? (lens-set second-lens '(1 2 3 4 5) 'a) '(1 a 3 4 5))
   (check-equal? (lens-set third-lens  '(1 2 3 4 5) 'a) '(1 2 a 4 5))
   (check-equal? (lens-set fourth-lens '(1 2 3 4 5) 'a) '(1 2 3 a 5))
-  (check-equal? (lens-set fifth-lens  '(1 2 3 4 5) 'a) '(1 2 3 4 a))
-  (check-equal? (lens-transform/list '(a (b c) (d e f)) (list-ref-nested-lens 2 1) symbol->string)
-                '(a (b c) (d "e" f))))
+  (check-equal? (lens-set fifth-lens  '(1 2 3 4 5) 'a) '(1 2 3 4 a)))

lens/main.rkt

@@ -17,6 +17,5 @@
    )
   focus-lens
   drop-lens
-  list-ref-nested-lens
   take-lens
   use-applicable-lenses!))

unstable/lens/compound.scrbl

@@ -3,6 +3,7 @@
 @(require scribble/eval
           lens/lenses-examples
           (for-label lens
+                     unstable/lens
                      racket/base
                      racket/contract))
 

unstable/lens/hash.rkt

@@ -2,25 +2,26 @@
 
 (provide
  (contract-out
-  [hash-ref-lens (-> any/c lens?)]))
+  [hash-ref-lens (-> any/c lens?)]
+  [hash-ref-nested-lens (->* () #:rest list? lens?)]))
 
 (require fancy-app
-         "base/main.rkt")
+         lens)
 
 (module+ test
   (require rackunit))
 
 
-(define (hash-ref-lens1 key)
+(define (hash-ref-lens key)
   (make-lens (hash-ref _ key)
              (hash-set _ key _)))
 
-(define (hash-ref-lens . keys)
-  (apply lens-thrush (map hash-ref-lens1 keys)))
+(define (hash-ref-nested-lens . keys)
+  (apply lens-thrush (map hash-ref-lens keys)))
 
 (module+ test
   (define a (hash-ref-lens 'a))
-  (define a-x (hash-ref-lens 'a 'x))
+  (define a-x (hash-ref-nested-lens 'a 'x))
   (let-lens [val ctxt] a (hash 'a 1 'b 2 'c 3)
     (check-equal? val 1)
     (check-equal? (ctxt 100) (hash 'a 100 'b 2 'c 3)))

unstable/lens/hash.scrbl

@@ -0,0 +1,32 @@
+#lang scribble/manual
+
+@(require scribble/eval
+          lens/lenses-examples
+          (for-label lens
+                     unstable/lens
+                     racket/base
+                     racket/contract))
+
+
+@title{Hash Lenses}
+
+@defmodule[unstable/lens/hash]
+
+@defproc[(hash-ref-lens [key any/c]) lens?]{
+  Constructs a lens that targets hashes and views the value
+  of @racket[key].
+  @lenses-unstable-examples[
+    (define foo-lens (hash-ref-lens 'foo))
+    (lens-view foo-lens (hash 'foo 10 'bar 20))
+    (lens-set foo-lens (hash 'foo 10 'bar 20) 1000)
+]}
+
+@defproc[(hash-ref-nested-lens [key any/c] ...) lens?]{
+  Contructs a lens that targets hashes with nested hashes
+  as values and views the value obtained by using each
+  @racket[key] in order.
+  @lenses-unstable-examples[
+    (define foo-bar-lens (hash-ref-nested-lens 'foo 'bar))
+    (lens-view foo-bar-lens (hash 'foo (hash 'bar 1)))
+    (lens-set foo-bar-lens (hash 'foo (hash 'bar 1)) 1000)
+]}

unstable/lens/list.rkt

@@ -0,0 +1,17 @@
+#lang racket
+
+(require lens)
+
+(module+ test
+  (require rackunit))
+
+(provide
+  (contract-out
+    [list-ref-nested-lens (->* () #:rest (listof exact-nonnegative-integer?) lens?)]))
+
+(define (list-ref-nested-lens . args)
+  (apply lens-thrush (map list-ref-lens args)))
+
+(module+ test
+  (check-equal? (lens-transform/list '(a (b c) (d e f)) (list-ref-nested-lens 2 1) symbol->string)
+                '(a (b c) (d "e" f))))

unstable/lens/list.scrbl

@@ -0,0 +1,21 @@
+#lang scribble/manual
+
+@(require scribble/eval
+          lens/lenses-examples
+          (for-label lens
+                     racket/base
+                     racket/contract))
+
+
+@title{List Lenses}
+
+@defmodule[unstable/lens/list]
+
+@defproc[(list-ref-nested-lens [index exact-nonnegative-integer?] ...) lens?]{
+  Constructs a lens that views into a tree made from nested lists.
+  Indexing starts from zero in the same was as @racket[list-ref-lens].
+  @lenses-unstable-examples[
+    (define first-of-second-lens (list-ref-nested-lens 1 0))
+    (lens-view first-of-second-lens '(1 (a b c) 2 3))
+    (lens-set first-of-second-lens '(1 (a b c) 2 3) 'foo)
+]}

unstable/lens/main.rkt

@@ -1,7 +1,11 @@
 #lang racket
 
 (require "syntax.rkt"
-         "compound.rkt")
+         "compound.rkt"
+         "list.rkt"
+         "hash.rkt")
 
 (provide (all-from-out "syntax.rkt"
-                       "compound.rkt"))
+                       "compound.rkt"
+                       "list.rkt"
+                       "hash.rkt"))

unstable/lens/main.scrbl

@@ -10,4 +10,6 @@ may change in future releases. Do not depend on
 this library being backwards-compatible.
 
 @include-section["compound.scrbl"]
+@include-section["list.scrbl"]
+@include-section["hash.scrbl"]
 @include-section["syntax.scrbl"]