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Add list lens docs

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JackFirth 2015-02-24 20:45:33 -08:00
parent db0486bef7
commit 087cb19eec
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lenses/lenses.scrbl
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@ -100,4 +100,29 @@ source code: @url["https://github.com/jackfirth/lenses"]
(define first-of-second-lens (lens-compose first-lens second-lens))
(lens-view first-of-second-lens '((1 a) (2 b) (3 c)))
(lens-set first-of-second-lens '((1 a) (2 b) (3 c)) 200)
]}
]}
@section{List lenses}
@defproc[(list-lens [n exact-nonnegative-integer?])
(lens/c list? any?)]{
Returns a lens for examining the @racket[n]th item of a list,
with indexing starting from zero.
@lenses-examples[
(lens-view (list-lens 3) '(a b c d e f g h))
(lens-set (list-lens 1) '(a b c d e f g h) 'FOO)
]}
@deftogether[(
@defthing[first-lens (lens/c list? any/c)]
@defthing[second-lens (lens/c list? any/c)]
@defthing[third-lens (lens/c list? any/c)]
@defthing[fourth-lens (lens/c list? any/c)]
@defthing[fifth-lens (lens/c list? any/c)])]{
Lenses for examiniming specific items of lists. Shorthands
for the common use cases of @racket[list-lens].
@lenses-examples[
(lens-view third-lens '(a b c d))
(lens-view (lens-compose second-lens fourth-lens)
'((a 1) (b 2) (c 3) (d 4)))
]}