add lenses/applicable

lenses/applicable.rkt

@@ -0,0 +1,42 @@
+#lang racket/base
+
+(provide (all-defined-out)
+         lens/c let-lens lens-view lens-set lens-transform lens-struct lens-proc)
+
+(require (prefix-in - "main.rkt")
+         (only-in "main.rkt"
+                  lens/c let-lens lens-view lens-set lens-transform lens-struct lens-proc))
+
+(define (make-lens getter setter)
+  (lens-struct (-make-lens getter setter)))
+
+(define (lens-compose . args)
+  (lens-struct (apply -lens-compose args)))
+
+(define identity-lens
+  (lens-struct -identity-lens))
+
+(define (list-lens n)
+  (lens-struct (-list-lens n)))
+
+(define first-lens (lens-struct -first-lens))
+(define second-lens (lens-struct -second-lens))
+(define third-lens (lens-struct -third-lens))
+(define fourth-lens (lens-struct -fourth-lens))
+(define fifth-lens (lens-struct -fifth-lens))
+
+(define (assoc-lens key #:is-equal? [key-equal? equal?])
+  (lens-struct (-assoc-lens key #:is-equal? key-equal?)))
+
+(define (assv-lens key)
+  (lens-struct (-assv-lens key)))
+
+(define (assq-lens key)
+  (lens-struct (-assq-lens key)))
+
+(define-syntax-rule (syntax-lens target-id pattern)
+  (lens-struct (-syntax-lens target-id pattern)))
+
+(define-syntax-rule (syntax-keyword-seq-lens kw)
+  (lens-struct (-syntax-keyword-seq-lens kw)))
+

lenses/lenses.scrbl

@@ -251,3 +251,12 @@ used directly as a getter procedure.
 Gets a lens function. If @racket[lens] is a lens function but not a lens
 struct, returns the @racket[lens].
 }
+
+@section{lenses/applicable}
+
+@defmodule[lenses/applicable]
+
+This module provides the same functions as @racketmodname[lenses], but lenses
+are provided as applicable lens structs, and functions that return lenses return
+lens structs.
+