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<pre><a name="line-1"></a><span class='hs-comment'>{-# LANGUAGE CPP #-}</span>
<a name="line-2"></a><span class='hs-comment'>{-# LANGUAGE Rank2Types #-}</span>
<a name="line-3"></a><span class='hs-comment'>{-# LANGUAGE MultiParamTypeClasses #-}</span>
<a name="line-4"></a><span class='hs-comment'>{-# LANGUAGE FlexibleInstances #-}</span>
<a name="line-5"></a>
<a name="line-6"></a>
<a name="line-7"></a><span class='hs-cpp'>#ifndef MIN_VERSION_profunctors</span>
<a name="line-8"></a><span class='hs-cpp'>#define MIN_VERSION_profunctors(x,y,z) 1</span>
<a name="line-9"></a><span class='hs-cpp'>#endif</span>
<a name="line-10"></a>
<a name="line-11"></a><span class='hs-cpp'>#if __GLASGOW_HASKELL__ < 708 || !(MIN_VERSION_profunctors(4,4,0))</span>
<a name="line-12"></a><span class='hs-comment'>{-# LANGUAGE Trustworthy #-}</span>
<a name="line-13"></a><span class='hs-cpp'>#endif</span>
<a name="line-14"></a>
<a name="line-15"></a><span class='hs-cpp'>#if __GLASGOW_HASKELL__ && __GLASGOW_HASKELL__ >= 704</span>
<a name="line-16"></a><span class='hs-comment'>{-# LANGUAGE NoPolyKinds #-}</span>
<a name="line-17"></a><span class='hs-comment'>{-# LANGUAGE NoDataKinds #-}</span>
<a name="line-18"></a><span class='hs-cpp'>#endif</span>
<a name="line-19"></a><span class='hs-comment'>-------------------------------------------------------------------------------</span>
<a name="line-20"></a><span class='hs-comment'>-- |</span>
<a name="line-21"></a><span class='hs-comment'>-- Module : Control.Lens.Getter</span>
<a name="line-22"></a><span class='hs-comment'>-- Copyright : (C) 2012-15 Edward Kmett</span>
<a name="line-23"></a><span class='hs-comment'>-- License : BSD-style (see the file LICENSE)</span>
<a name="line-24"></a><span class='hs-comment'>-- Maintainer : Edward Kmett <ekmett@gmail.com></span>
<a name="line-25"></a><span class='hs-comment'>-- Stability : provisional</span>
<a name="line-26"></a><span class='hs-comment'>-- Portability : Rank2Types</span>
<a name="line-27"></a><span class='hs-comment'>--</span>
<a name="line-28"></a><span class='hs-comment'>--</span>
<a name="line-29"></a><span class='hs-comment'>-- A @'Getter' s a@ is just any function @(s -> a)@, which we've flipped</span>
<a name="line-30"></a><span class='hs-comment'>-- into continuation passing style, @(a -> r) -> s -> r@ and decorated</span>
<a name="line-31"></a><span class='hs-comment'>-- with 'Const' to obtain:</span>
<a name="line-32"></a><span class='hs-comment'>--</span>
<a name="line-33"></a><span class='hs-comment'>-- @type 'Getting' r s a = (a -> 'Const' r a) -> s -> 'Const' r s@</span>
<a name="line-34"></a><span class='hs-comment'>--</span>
<a name="line-35"></a><span class='hs-comment'>-- If we restrict access to knowledge about the type 'r', we could get:</span>
<a name="line-36"></a><span class='hs-comment'>--</span>
<a name="line-37"></a><span class='hs-comment'>-- @type 'Getter' s a = forall r. 'Getting' r s a@</span>
<a name="line-38"></a><span class='hs-comment'>--</span>
<a name="line-39"></a><span class='hs-comment'>-- However, for 'Getter' (but not for 'Getting') we actually permit any</span>
<a name="line-40"></a><span class='hs-comment'>-- functor @f@ which is an instance of both 'Functor' and 'Contravariant':</span>
<a name="line-41"></a><span class='hs-comment'>--</span>
<a name="line-42"></a><span class='hs-comment'>-- @type 'Getter' s a = forall f. ('Contravariant' f, 'Functor' f) => (a -> f a) -> s -> f s@</span>
<a name="line-43"></a><span class='hs-comment'>--</span>
<a name="line-44"></a><span class='hs-comment'>-- Everything you can do with a function, you can do with a 'Getter', but</span>
<a name="line-45"></a><span class='hs-comment'>-- note that because of the continuation passing style ('.') composes them</span>
<a name="line-46"></a><span class='hs-comment'>-- in the opposite order.</span>
<a name="line-47"></a><span class='hs-comment'>--</span>
<a name="line-48"></a><span class='hs-comment'>-- Since it is only a function, every 'Getter' obviously only retrieves a</span>
<a name="line-49"></a><span class='hs-comment'>-- single value for a given input.</span>
<a name="line-50"></a><span class='hs-comment'>--</span>
<a name="line-51"></a><span class='hs-comment'>-------------------------------------------------------------------------------</span>
<a name="line-52"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Lens</span><span class='hs-varop'>.</span><span class='hs-conid'>Getter</span>
<a name="line-53"></a> <span class='hs-layout'>(</span>
<a name="line-54"></a> <span class='hs-comment'>-- * Getters</span>
<a name="line-55"></a> <span class='hs-conid'>Getter</span><span class='hs-layout'>,</span> <span class='hs-conid'>IndexedGetter</span>
<a name="line-56"></a> <span class='hs-layout'>,</span> <span class='hs-conid'>Getting</span><span class='hs-layout'>,</span> <span class='hs-conid'>IndexedGetting</span>
<a name="line-57"></a> <span class='hs-layout'>,</span> <span class='hs-conid'>Accessing</span>
<a name="line-58"></a> <span class='hs-comment'>-- * Building Getters</span>
<a name="line-59"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>to</span>
<a name="line-60"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>ito</span>
<a name="line-61"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>like</span>
<a name="line-62"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>ilike</span>
<a name="line-63"></a> <span class='hs-comment'>-- * Combinators for Getters and Folds</span>
<a name="line-64"></a> <span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-varop'>^.</span><span class='hs-layout'>)</span>
<a name="line-65"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>view</span><span class='hs-layout'>,</span> <span class='hs-varid'>views</span>
<a name="line-66"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>use</span><span class='hs-layout'>,</span> <span class='hs-varid'>uses</span>
<a name="line-67"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>listening</span><span class='hs-layout'>,</span> <span class='hs-varid'>listenings</span>
<a name="line-68"></a> <span class='hs-comment'>-- * Indexed Getters</span>
<a name="line-69"></a> <span class='hs-comment'>-- ** Indexed Getter Combinators</span>
<a name="line-70"></a> <span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-varop'>^@.</span><span class='hs-layout'>)</span>
<a name="line-71"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>iview</span><span class='hs-layout'>,</span> <span class='hs-varid'>iviews</span>
<a name="line-72"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>iuse</span><span class='hs-layout'>,</span> <span class='hs-varid'>iuses</span>
<a name="line-73"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>ilistening</span><span class='hs-layout'>,</span> <span class='hs-varid'>ilistenings</span>
<a name="line-74"></a> <span class='hs-comment'>-- * Implementation Details</span>
<a name="line-75"></a> <span class='hs-layout'>,</span> <span class='hs-conid'>Contravariant</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span>
<a name="line-76"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>getting</span>
<a name="line-77"></a> <span class='hs-layout'>,</span> <span class='hs-conid'>Const</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span>
<a name="line-78"></a> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-79"></a>
<a name="line-80"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Applicative</span>
<a name="line-81"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Lens</span><span class='hs-varop'>.</span><span class='hs-conid'>Internal</span><span class='hs-varop'>.</span><span class='hs-conid'>Indexed</span>
<a name="line-82"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Lens</span><span class='hs-varop'>.</span><span class='hs-conid'>Type</span>
<a name="line-83"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span><span class='hs-varop'>.</span><span class='hs-conid'>Reader</span><span class='hs-varop'>.</span><span class='hs-conid'>Class</span> <span class='hs-keyword'>as</span> <span class='hs-conid'>Reader</span>
<a name="line-84"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span><span class='hs-varop'>.</span><span class='hs-conid'>State</span> <span class='hs-keyword'>as</span> <span class='hs-conid'>State</span>
<a name="line-85"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span><span class='hs-varop'>.</span><span class='hs-conid'>Writer</span> <span class='hs-keyword'>as</span> <span class='hs-conid'>Writer</span>
<a name="line-86"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Functor</span><span class='hs-varop'>.</span><span class='hs-conid'>Contravariant</span>
<a name="line-87"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Profunctor</span>
<a name="line-88"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Profunctor</span><span class='hs-varop'>.</span><span class='hs-conid'>Unsafe</span>
<a name="line-89"></a>
<a name="line-90"></a><span class='hs-comment'>-- $setup</span>
<a name="line-91"></a><span class='hs-comment'>-- >>> :set -XNoOverloadedStrings</span>
<a name="line-92"></a><span class='hs-comment'>-- >>> import Control.Lens</span>
<a name="line-93"></a><span class='hs-comment'>-- >>> import Data.List.Lens</span>
<a name="line-94"></a><span class='hs-comment'>-- >>> import Debug.SimpleReflect.Expr</span>
<a name="line-95"></a><span class='hs-comment'>-- >>> import Debug.SimpleReflect.Vars as Vars hiding (f,g)</span>
<a name="line-96"></a><span class='hs-comment'>-- >>> let f :: Expr -> Expr; f = Debug.SimpleReflect.Vars.f</span>
<a name="line-97"></a><span class='hs-comment'>-- >>> let g :: Expr -> Expr; g = Debug.SimpleReflect.Vars.g</span>
<a name="line-98"></a>
<a name="line-99"></a><span class='hs-keyword'>infixl</span> <span class='hs-num'>8</span> <span class='hs-varop'>^.</span><span class='hs-layout'>,</span> <span class='hs-varop'>^@.</span>
<a name="line-100"></a>
<a name="line-101"></a><span class='hs-comment'>-------------------------------------------------------------------------------</span>
<a name="line-102"></a><span class='hs-comment'>-- Getters</span>
<a name="line-103"></a><span class='hs-comment'>-------------------------------------------------------------------------------</span>
<a name="line-104"></a>
<a name="line-105"></a><a name="to"></a><span class='hs-comment'>-- | Build an (index-preserving) 'Getter' from an arbitrary Haskell function.</span>
<a name="line-106"></a><span class='hs-comment'>--</span>
<a name="line-107"></a><span class='hs-comment'>-- @</span>
<a name="line-108"></a><span class='hs-comment'>-- 'to' f '.' 'to' g ≡ 'to' (g '.' f)</span>
<a name="line-109"></a><span class='hs-comment'>-- @</span>
<a name="line-110"></a><span class='hs-comment'>--</span>
<a name="line-111"></a><span class='hs-comment'>-- @</span>
<a name="line-112"></a><span class='hs-comment'>-- a '^.' 'to' f ≡ f a</span>
<a name="line-113"></a><span class='hs-comment'>-- @</span>
<a name="line-114"></a><span class='hs-comment'>--</span>
<a name="line-115"></a><span class='hs-comment'>-- >>> a ^.to f</span>
<a name="line-116"></a><span class='hs-comment'>-- f a</span>
<a name="line-117"></a><span class='hs-comment'>--</span>
<a name="line-118"></a><span class='hs-comment'>-- >>> ("hello","world")^.to snd</span>
<a name="line-119"></a><span class='hs-comment'>-- "world"</span>
<a name="line-120"></a><span class='hs-comment'>--</span>
<a name="line-121"></a><span class='hs-comment'>-- >>> 5^.to succ</span>
<a name="line-122"></a><span class='hs-comment'>-- 6</span>
<a name="line-123"></a><span class='hs-comment'>--</span>
<a name="line-124"></a><span class='hs-comment'>-- >>> (0, -5)^._2.to abs</span>
<a name="line-125"></a><span class='hs-comment'>-- 5</span>
<a name="line-126"></a><span class='hs-comment'>--</span>
<a name="line-127"></a><span class='hs-comment'>-- @</span>
<a name="line-128"></a><span class='hs-comment'>-- 'to' :: (s -> a) -> 'IndexPreservingGetter' s a</span>
<a name="line-129"></a><span class='hs-comment'>-- @</span>
<a name="line-130"></a><span class='hs-definition'>to</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Profunctor</span> <span class='hs-varid'>p</span><span class='hs-layout'>,</span> <span class='hs-conid'>Contravariant</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Optic'</span> <span class='hs-varid'>p</span> <span class='hs-varid'>f</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span>
<a name="line-131"></a><span class='hs-definition'>to</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>dimap</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-varid'>contramap</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span>
<a name="line-132"></a><span class='hs-comment'>{-# INLINE to #-}</span>
<a name="line-133"></a>
<a name="line-134"></a><a name="ito"></a><span class='hs-comment'>-- |</span>
<a name="line-135"></a><span class='hs-comment'>-- @</span>
<a name="line-136"></a><span class='hs-comment'>-- 'ito' :: (s -> (i, a)) -> 'IndexedGetter' i s a</span>
<a name="line-137"></a><span class='hs-comment'>-- @</span>
<a name="line-138"></a><span class='hs-definition'>ito</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Indexable</span> <span class='hs-varid'>i</span> <span class='hs-varid'>p</span><span class='hs-layout'>,</span> <span class='hs-conid'>Contravariant</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span><span class='hs-layout'>,</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Over'</span> <span class='hs-varid'>p</span> <span class='hs-varid'>f</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span>
<a name="line-139"></a><span class='hs-definition'>ito</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>dimap</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-varid'>contramap</span> <span class='hs-layout'>(</span><span class='hs-varid'>snd</span> <span class='hs-varop'>.</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span> <span class='hs-varid'>uncurry</span> <span class='hs-varop'>.</span> <span class='hs-varid'>indexed</span>
<a name="line-140"></a><span class='hs-comment'>{-# INLINE ito #-}</span>
<a name="line-141"></a>
<a name="line-142"></a>
<a name="line-143"></a><a name="like"></a><span class='hs-comment'>-- | Build an constant-valued (index-preserving) 'Getter' from an arbitrary Haskell value.</span>
<a name="line-144"></a><span class='hs-comment'>--</span>
<a name="line-145"></a><span class='hs-comment'>-- @</span>
<a name="line-146"></a><span class='hs-comment'>-- 'like' a '.' 'like' b ≡ 'like' b</span>
<a name="line-147"></a><span class='hs-comment'>-- a '^.' 'like' b ≡ b</span>
<a name="line-148"></a><span class='hs-comment'>-- a '^.' 'like' b ≡ a '^.' 'to' ('const' b)</span>
<a name="line-149"></a><span class='hs-comment'>-- @</span>
<a name="line-150"></a><span class='hs-comment'>--</span>
<a name="line-151"></a><span class='hs-comment'>-- This can be useful as a second case 'failing' a 'Fold'</span>
<a name="line-152"></a><span class='hs-comment'>-- e.g. @foo `failing` 'like' 0@</span>
<a name="line-153"></a><span class='hs-comment'>--</span>
<a name="line-154"></a><span class='hs-comment'>-- @</span>
<a name="line-155"></a><span class='hs-comment'>-- 'like' :: a -> 'IndexPreservingGetter' s a</span>
<a name="line-156"></a><span class='hs-comment'>-- @</span>
<a name="line-157"></a><span class='hs-definition'>like</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Profunctor</span> <span class='hs-varid'>p</span><span class='hs-layout'>,</span> <span class='hs-conid'>Contravariant</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Optic'</span> <span class='hs-varid'>p</span> <span class='hs-varid'>f</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span>
<a name="line-158"></a><span class='hs-definition'>like</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>to</span> <span class='hs-layout'>(</span><span class='hs-varid'>const</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-159"></a><span class='hs-comment'>{-# INLINE like #-}</span>
<a name="line-160"></a>
<a name="line-161"></a><a name="ilike"></a><span class='hs-comment'>-- |</span>
<a name="line-162"></a><span class='hs-comment'>-- @</span>
<a name="line-163"></a><span class='hs-comment'>-- 'ilike' :: i -> a -> 'IndexedGetter' i s a</span>
<a name="line-164"></a><span class='hs-comment'>-- @</span>
<a name="line-165"></a><span class='hs-definition'>ilike</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Indexable</span> <span class='hs-varid'>i</span> <span class='hs-varid'>p</span><span class='hs-layout'>,</span> <span class='hs-conid'>Contravariant</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Over'</span> <span class='hs-varid'>p</span> <span class='hs-varid'>f</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span>
<a name="line-166"></a><span class='hs-definition'>ilike</span> <span class='hs-varid'>i</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ito</span> <span class='hs-layout'>(</span><span class='hs-varid'>const</span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span><span class='hs-layout'>,</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-167"></a><span class='hs-comment'>{-# INLINE ilike #-}</span>
<a name="line-168"></a>
<a name="line-169"></a><a name="Getting"></a><span class='hs-comment'>-- | When you see this in a type signature it indicates that you can</span>
<a name="line-170"></a><a name="Getting"></a><span class='hs-comment'>-- pass the function a 'Lens', 'Getter',</span>
<a name="line-171"></a><a name="Getting"></a><span class='hs-comment'>-- 'Control.Lens.Traversal.Traversal', 'Control.Lens.Fold.Fold',</span>
<a name="line-172"></a><a name="Getting"></a><span class='hs-comment'>-- 'Control.Lens.Prism.Prism', 'Control.Lens.Iso.Iso', or one of</span>
<a name="line-173"></a><a name="Getting"></a><span class='hs-comment'>-- the indexed variants, and it will just \"do the right thing\".</span>
<a name="line-174"></a><a name="Getting"></a><span class='hs-comment'>--</span>
<a name="line-175"></a><a name="Getting"></a><span class='hs-comment'>-- Most 'Getter' combinators are able to be used with both a 'Getter' or a</span>
<a name="line-176"></a><a name="Getting"></a><span class='hs-comment'>-- 'Control.Lens.Fold.Fold' in limited situations, to do so, they need to be</span>
<a name="line-177"></a><a name="Getting"></a><span class='hs-comment'>-- monomorphic in what we are going to extract with 'Control.Applicative.Const'. To be compatible</span>
<a name="line-178"></a><a name="Getting"></a><span class='hs-comment'>-- with 'Lens', 'Control.Lens.Traversal.Traversal' and</span>
<a name="line-179"></a><a name="Getting"></a><span class='hs-comment'>-- 'Control.Lens.Iso.Iso' we also restricted choices of the irrelevant @t@ and</span>
<a name="line-180"></a><a name="Getting"></a><span class='hs-comment'>-- @b@ parameters.</span>
<a name="line-181"></a><a name="Getting"></a><span class='hs-comment'>--</span>
<a name="line-182"></a><a name="Getting"></a><span class='hs-comment'>-- If a function accepts a @'Getting' r s a@, then when @r@ is a 'Data.Monoid.Monoid', then</span>
<a name="line-183"></a><a name="Getting"></a><span class='hs-comment'>-- you can pass a 'Control.Lens.Fold.Fold' (or</span>
<a name="line-184"></a><a name="Getting"></a><span class='hs-comment'>-- 'Control.Lens.Traversal.Traversal'), otherwise you can only pass this a</span>
<a name="line-185"></a><a name="Getting"></a><span class='hs-comment'>-- 'Getter' or 'Lens'.</span>
<a name="line-186"></a><a name="Getting"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>Getting</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Const</span> <span class='hs-varid'>r</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Const</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span>
<a name="line-187"></a>
<a name="line-188"></a><a name="IndexedGetting"></a><span class='hs-comment'>-- | Used to consume an 'Control.Lens.Fold.IndexedFold'.</span>
<a name="line-189"></a><a name="IndexedGetting"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>IndexedGetting</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Indexed</span> <span class='hs-varid'>i</span> <span class='hs-varid'>a</span> <span class='hs-layout'>(</span><span class='hs-conid'>Const</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Const</span> <span class='hs-varid'>m</span> <span class='hs-varid'>s</span>
<a name="line-190"></a>
<a name="line-191"></a><a name="Accessing"></a><span class='hs-comment'>-- | This is a convenient alias used when consuming (indexed) getters and (indexed) folds</span>
<a name="line-192"></a><a name="Accessing"></a><span class='hs-comment'>-- in a highly general fashion.</span>
<a name="line-193"></a><a name="Accessing"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>Accessing</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>p</span> <span class='hs-varid'>a</span> <span class='hs-layout'>(</span><span class='hs-conid'>Const</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Const</span> <span class='hs-varid'>m</span> <span class='hs-varid'>s</span>
<a name="line-194"></a>
<a name="line-195"></a><span class='hs-comment'>-------------------------------------------------------------------------------</span>
<a name="line-196"></a><span class='hs-comment'>-- Getting Values</span>
<a name="line-197"></a><span class='hs-comment'>-------------------------------------------------------------------------------</span>
<a name="line-198"></a>
<a name="line-199"></a><a name="view"></a><span class='hs-comment'>-- | View the value pointed to by a 'Getter', 'Control.Lens.Iso.Iso' or</span>
<a name="line-200"></a><span class='hs-comment'>-- 'Lens' or the result of folding over all the results of a</span>
<a name="line-201"></a><span class='hs-comment'>-- 'Control.Lens.Fold.Fold' or 'Control.Lens.Traversal.Traversal' that points</span>
<a name="line-202"></a><span class='hs-comment'>-- at a monoidal value.</span>
<a name="line-203"></a><span class='hs-comment'>--</span>
<a name="line-204"></a><span class='hs-comment'>-- @</span>
<a name="line-205"></a><span class='hs-comment'>-- 'view' '.' 'to' ≡ 'id'</span>
<a name="line-206"></a><span class='hs-comment'>-- @</span>
<a name="line-207"></a><span class='hs-comment'>--</span>
<a name="line-208"></a><span class='hs-comment'>-- >>> view (to f) a</span>
<a name="line-209"></a><span class='hs-comment'>-- f a</span>
<a name="line-210"></a><span class='hs-comment'>--</span>
<a name="line-211"></a><span class='hs-comment'>-- >>> view _2 (1,"hello")</span>
<a name="line-212"></a><span class='hs-comment'>-- "hello"</span>
<a name="line-213"></a><span class='hs-comment'>--</span>
<a name="line-214"></a><span class='hs-comment'>-- >>> view (to succ) 5</span>
<a name="line-215"></a><span class='hs-comment'>-- 6</span>
<a name="line-216"></a><span class='hs-comment'>--</span>
<a name="line-217"></a><span class='hs-comment'>-- >>> view (_2._1) ("hello",("world","!!!"))</span>
<a name="line-218"></a><span class='hs-comment'>-- "world"</span>
<a name="line-219"></a><span class='hs-comment'>--</span>
<a name="line-220"></a><span class='hs-comment'>--</span>
<a name="line-221"></a><span class='hs-comment'>-- As 'view' is commonly used to access the target of a 'Getter' or obtain a monoidal summary of the targets of a 'Fold',</span>
<a name="line-222"></a><span class='hs-comment'>-- It may be useful to think of it as having one of these more restricted signatures:</span>
<a name="line-223"></a><span class='hs-comment'>--</span>
<a name="line-224"></a><span class='hs-comment'>-- @</span>
<a name="line-225"></a><span class='hs-comment'>-- 'view' :: 'Getter' s a -> s -> a</span>
<a name="line-226"></a><span class='hs-comment'>-- 'view' :: 'Data.Monoid.Monoid' m => 'Control.Lens.Fold.Fold' s m -> s -> m</span>
<a name="line-227"></a><span class='hs-comment'>-- 'view' :: 'Control.Lens.Iso.Iso'' s a -> s -> a</span>
<a name="line-228"></a><span class='hs-comment'>-- 'view' :: 'Lens'' s a -> s -> a</span>
<a name="line-229"></a><span class='hs-comment'>-- 'view' :: 'Data.Monoid.Monoid' m => 'Control.Lens.Traversal.Traversal'' s m -> s -> m</span>
<a name="line-230"></a><span class='hs-comment'>-- @</span>
<a name="line-231"></a><span class='hs-comment'>--</span>
<a name="line-232"></a><span class='hs-comment'>-- In a more general setting, such as when working with a 'Monad' transformer stack you can use:</span>
<a name="line-233"></a><span class='hs-comment'>--</span>
<a name="line-234"></a><span class='hs-comment'>-- @</span>
<a name="line-235"></a><span class='hs-comment'>-- 'view' :: 'MonadReader' s m => 'Getter' s a -> m a</span>
<a name="line-236"></a><span class='hs-comment'>-- 'view' :: ('MonadReader' s m, 'Data.Monoid.Monoid' a) => 'Control.Lens.Fold.Fold' s a -> m a</span>
<a name="line-237"></a><span class='hs-comment'>-- 'view' :: 'MonadReader' s m => 'Control.Lens.Iso.Iso'' s a -> m a</span>
<a name="line-238"></a><span class='hs-comment'>-- 'view' :: 'MonadReader' s m => 'Lens'' s a -> m a</span>
<a name="line-239"></a><span class='hs-comment'>-- 'view' :: ('MonadReader' s m, 'Data.Monoid.Monoid' a) => 'Control.Lens.Traversal.Traversal'' s a -> m a</span>
<a name="line-240"></a><span class='hs-comment'>-- @</span>
<a name="line-241"></a><span class='hs-definition'>view</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadReader</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Getting</span> <span class='hs-varid'>a</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-242"></a><span class='hs-definition'>view</span> <span class='hs-varid'>l</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Reader</span><span class='hs-varop'>.</span><span class='hs-varid'>asks</span> <span class='hs-layout'>(</span><span class='hs-varid'>getConst</span> <span class='hs-cpp'>#.</span> <span class='hs-varid'>l</span> <span class='hs-conid'>Const</span><span class='hs-layout'>)</span>
<a name="line-243"></a><span class='hs-comment'>{-# INLINE view #-}</span>
<a name="line-244"></a>
<a name="line-245"></a><a name="views"></a><span class='hs-comment'>-- | View a function of the value pointed to by a 'Getter' or 'Lens' or the result of</span>
<a name="line-246"></a><span class='hs-comment'>-- folding over the result of mapping the targets of a 'Control.Lens.Fold.Fold' or</span>
<a name="line-247"></a><span class='hs-comment'>-- 'Control.Lens.Traversal.Traversal'.</span>
<a name="line-248"></a><span class='hs-comment'>--</span>
<a name="line-249"></a><span class='hs-comment'>-- @</span>
<a name="line-250"></a><span class='hs-comment'>-- 'views' l f ≡ 'view' (l '.' 'to' f)</span>
<a name="line-251"></a><span class='hs-comment'>-- @</span>
<a name="line-252"></a><span class='hs-comment'>--</span>
<a name="line-253"></a><span class='hs-comment'>-- >>> views (to f) g a</span>
<a name="line-254"></a><span class='hs-comment'>-- g (f a)</span>
<a name="line-255"></a><span class='hs-comment'>--</span>
<a name="line-256"></a><span class='hs-comment'>-- >>> views _2 length (1,"hello")</span>
<a name="line-257"></a><span class='hs-comment'>-- 5</span>
<a name="line-258"></a><span class='hs-comment'>--</span>
<a name="line-259"></a><span class='hs-comment'>-- As 'views' is commonly used to access the target of a 'Getter' or obtain a monoidal summary of the targets of a 'Fold',</span>
<a name="line-260"></a><span class='hs-comment'>-- It may be useful to think of it as having one of these more restricted signatures:</span>
<a name="line-261"></a><span class='hs-comment'>--</span>
<a name="line-262"></a><span class='hs-comment'>-- @</span>
<a name="line-263"></a><span class='hs-comment'>-- 'views' :: 'Getter' s a -> (a -> r) -> s -> r</span>
<a name="line-264"></a><span class='hs-comment'>-- 'views' :: 'Data.Monoid.Monoid' m => 'Control.Lens.Fold.Fold' s a -> (a -> m) -> s -> m</span>
<a name="line-265"></a><span class='hs-comment'>-- 'views' :: 'Control.Lens.Iso.Iso'' s a -> (a -> r) -> s -> r</span>
<a name="line-266"></a><span class='hs-comment'>-- 'views' :: 'Lens'' s a -> (a -> r) -> s -> r</span>
<a name="line-267"></a><span class='hs-comment'>-- 'views' :: 'Data.Monoid.Monoid' m => 'Control.Lens.Traversal.Traversal'' s a -> (a -> m) -> s -> m</span>
<a name="line-268"></a><span class='hs-comment'>-- @</span>
<a name="line-269"></a><span class='hs-comment'>--</span>
<a name="line-270"></a><span class='hs-comment'>-- In a more general setting, such as when working with a 'Monad' transformer stack you can use:</span>
<a name="line-271"></a><span class='hs-comment'>--</span>
<a name="line-272"></a><span class='hs-comment'>-- @</span>
<a name="line-273"></a><span class='hs-comment'>-- 'views' :: 'MonadReader' s m => 'Getter' s a -> (a -> r) -> m r</span>
<a name="line-274"></a><span class='hs-comment'>-- 'views' :: ('MonadReader' s m, 'Data.Monoid.Monoid' r) => 'Control.Lens.Fold.Fold' s a -> (a -> r) -> m r</span>
<a name="line-275"></a><span class='hs-comment'>-- 'views' :: 'MonadReader' s m => 'Control.Lens.Iso.Iso'' s a -> (a -> r) -> m r</span>
<a name="line-276"></a><span class='hs-comment'>-- 'views' :: 'MonadReader' s m => 'Lens'' s a -> (a -> r) -> m r</span>
<a name="line-277"></a><span class='hs-comment'>-- 'views' :: ('MonadReader' s m, 'Data.Monoid.Monoid' r) => 'Control.Lens.Traversal.Traversal'' s a -> (a -> r) -> m r</span>
<a name="line-278"></a><span class='hs-comment'>-- @</span>
<a name="line-279"></a><span class='hs-comment'>--</span>
<a name="line-280"></a><span class='hs-comment'>-- @</span>
<a name="line-281"></a><span class='hs-comment'>-- 'views' :: 'MonadReader' s m => 'Getting' r s a -> (a -> r) -> m r</span>
<a name="line-282"></a><span class='hs-comment'>-- @</span>
<a name="line-283"></a><span class='hs-definition'>views</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadReader</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>LensLike'</span> <span class='hs-layout'>(</span><span class='hs-conid'>Const</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span>
<a name="line-284"></a><span class='hs-definition'>views</span> <span class='hs-varid'>l</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Reader</span><span class='hs-varop'>.</span><span class='hs-varid'>asks</span> <span class='hs-layout'>(</span><span class='hs-varid'>getConst</span> <span class='hs-cpp'>#.</span> <span class='hs-varid'>l</span> <span class='hs-layout'>(</span><span class='hs-conid'>Const</span> <span class='hs-cpp'>#.</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-285"></a><span class='hs-comment'>{-# INLINE views #-}</span>
<a name="line-286"></a>
<a name="line-287"></a><a name="%5e."></a><span class='hs-comment'>-- | View the value pointed to by a 'Getter' or 'Lens' or the</span>
<a name="line-288"></a><span class='hs-comment'>-- result of folding over all the results of a 'Control.Lens.Fold.Fold' or</span>
<a name="line-289"></a><span class='hs-comment'>-- 'Control.Lens.Traversal.Traversal' that points at a monoidal values.</span>
<a name="line-290"></a><span class='hs-comment'>--</span>
<a name="line-291"></a><span class='hs-comment'>-- This is the same operation as 'view' with the arguments flipped.</span>
<a name="line-292"></a><span class='hs-comment'>--</span>
<a name="line-293"></a><span class='hs-comment'>-- The fixity and semantics are such that subsequent field accesses can be</span>
<a name="line-294"></a><span class='hs-comment'>-- performed with ('Prelude..').</span>
<a name="line-295"></a><span class='hs-comment'>--</span>
<a name="line-296"></a><span class='hs-comment'>-- >>> (a,b)^._2</span>
<a name="line-297"></a><span class='hs-comment'>-- b</span>
<a name="line-298"></a><span class='hs-comment'>--</span>
<a name="line-299"></a><span class='hs-comment'>-- >>> ("hello","world")^._2</span>
<a name="line-300"></a><span class='hs-comment'>-- "world"</span>
<a name="line-301"></a><span class='hs-comment'>--</span>
<a name="line-302"></a><span class='hs-comment'>-- >>> import Data.Complex</span>
<a name="line-303"></a><span class='hs-comment'>-- >>> ((0, 1 :+ 2), 3)^._1._2.to magnitude</span>
<a name="line-304"></a><span class='hs-comment'>-- 2.23606797749979</span>
<a name="line-305"></a><span class='hs-comment'>--</span>
<a name="line-306"></a><span class='hs-comment'>-- @</span>
<a name="line-307"></a><span class='hs-comment'>-- ('^.') :: s -> 'Getter' s a -> a</span>
<a name="line-308"></a><span class='hs-comment'>-- ('^.') :: 'Data.Monoid.Monoid' m => s -> 'Control.Lens.Fold.Fold' s m -> m</span>
<a name="line-309"></a><span class='hs-comment'>-- ('^.') :: s -> 'Control.Lens.Iso.Iso'' s a -> a</span>
<a name="line-310"></a><span class='hs-comment'>-- ('^.') :: s -> 'Lens'' s a -> a</span>
<a name="line-311"></a><span class='hs-comment'>-- ('^.') :: 'Data.Monoid.Monoid' m => s -> 'Control.Lens.Traversal.Traversal'' s m -> m</span>
<a name="line-312"></a><span class='hs-comment'>-- @</span>
<a name="line-313"></a><span class='hs-layout'>(</span><span class='hs-varop'>^.</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Getting</span> <span class='hs-varid'>a</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span>
<a name="line-314"></a><a name="s"></a><span class='hs-definition'>s</span> <span class='hs-varop'>^.</span> <span class='hs-varid'>l</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>getConst</span> <span class='hs-layout'>(</span><span class='hs-varid'>l</span> <span class='hs-conid'>Const</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span>
<a name="line-315"></a><span class='hs-comment'>{-# INLINE (^.) #-}</span>
<a name="line-316"></a>
<a name="line-317"></a><span class='hs-comment'>-------------------------------------------------------------------------------</span>
<a name="line-318"></a><span class='hs-comment'>-- MonadState</span>
<a name="line-319"></a><span class='hs-comment'>-------------------------------------------------------------------------------</span>
<a name="line-320"></a>
<a name="line-321"></a><a name="use"></a><span class='hs-comment'>-- | Use the target of a 'Lens', 'Control.Lens.Iso.Iso', or</span>
<a name="line-322"></a><span class='hs-comment'>-- 'Getter' in the current state, or use a summary of a</span>
<a name="line-323"></a><span class='hs-comment'>-- 'Control.Lens.Fold.Fold' or 'Control.Lens.Traversal.Traversal' that points</span>
<a name="line-324"></a><span class='hs-comment'>-- to a monoidal value.</span>
<a name="line-325"></a><span class='hs-comment'>--</span>
<a name="line-326"></a><span class='hs-comment'>-- >>> evalState (use _1) (a,b)</span>
<a name="line-327"></a><span class='hs-comment'>-- a</span>
<a name="line-328"></a><span class='hs-comment'>--</span>
<a name="line-329"></a><span class='hs-comment'>-- >>> evalState (use _1) ("hello","world")</span>
<a name="line-330"></a><span class='hs-comment'>-- "hello"</span>
<a name="line-331"></a><span class='hs-comment'>--</span>
<a name="line-332"></a><span class='hs-comment'>-- @</span>
<a name="line-333"></a><span class='hs-comment'>-- 'use' :: 'MonadState' s m => 'Getter' s a -> m a</span>
<a name="line-334"></a><span class='hs-comment'>-- 'use' :: ('MonadState' s m, 'Data.Monoid.Monoid' r) => 'Control.Lens.Fold.Fold' s r -> m r</span>
<a name="line-335"></a><span class='hs-comment'>-- 'use' :: 'MonadState' s m => 'Control.Lens.Iso.Iso'' s a -> m a</span>
<a name="line-336"></a><span class='hs-comment'>-- 'use' :: 'MonadState' s m => 'Lens'' s a -> m a</span>
<a name="line-337"></a><span class='hs-comment'>-- 'use' :: ('MonadState' s m, 'Data.Monoid.Monoid' r) => 'Control.Lens.Traversal.Traversal'' s r -> m r</span>
<a name="line-338"></a><span class='hs-comment'>-- @</span>
<a name="line-339"></a><span class='hs-definition'>use</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadState</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Getting</span> <span class='hs-varid'>a</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-340"></a><span class='hs-definition'>use</span> <span class='hs-varid'>l</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>State</span><span class='hs-varop'>.</span><span class='hs-varid'>gets</span> <span class='hs-layout'>(</span><span class='hs-varid'>view</span> <span class='hs-varid'>l</span><span class='hs-layout'>)</span>
<a name="line-341"></a><span class='hs-comment'>{-# INLINE use #-}</span>
<a name="line-342"></a>
<a name="line-343"></a><a name="uses"></a><span class='hs-comment'>-- | Use the target of a 'Lens', 'Control.Lens.Iso.Iso' or</span>
<a name="line-344"></a><span class='hs-comment'>-- 'Getter' in the current state, or use a summary of a</span>
<a name="line-345"></a><span class='hs-comment'>-- 'Control.Lens.Fold.Fold' or 'Control.Lens.Traversal.Traversal' that</span>
<a name="line-346"></a><span class='hs-comment'>-- points to a monoidal value.</span>
<a name="line-347"></a><span class='hs-comment'>--</span>
<a name="line-348"></a><span class='hs-comment'>-- >>> evalState (uses _1 length) ("hello","world")</span>
<a name="line-349"></a><span class='hs-comment'>-- 5</span>
<a name="line-350"></a><span class='hs-comment'>--</span>
<a name="line-351"></a><span class='hs-comment'>-- @</span>
<a name="line-352"></a><span class='hs-comment'>-- 'uses' :: 'MonadState' s m => 'Getter' s a -> (a -> r) -> m r</span>
<a name="line-353"></a><span class='hs-comment'>-- 'uses' :: ('MonadState' s m, 'Data.Monoid.Monoid' r) => 'Control.Lens.Fold.Fold' s a -> (a -> r) -> m r</span>
<a name="line-354"></a><span class='hs-comment'>-- 'uses' :: 'MonadState' s m => 'Lens'' s a -> (a -> r) -> m r</span>
<a name="line-355"></a><span class='hs-comment'>-- 'uses' :: 'MonadState' s m => 'Control.Lens.Iso.Iso'' s a -> (a -> r) -> m r</span>
<a name="line-356"></a><span class='hs-comment'>-- 'uses' :: ('MonadState' s m, 'Data.Monoid.Monoid' r) => 'Control.Lens.Traversal.Traversal'' s a -> (a -> r) -> m r</span>
<a name="line-357"></a><span class='hs-comment'>-- @</span>
<a name="line-358"></a><span class='hs-comment'>--</span>
<a name="line-359"></a><span class='hs-comment'>-- @</span>
<a name="line-360"></a><span class='hs-comment'>-- 'uses' :: 'MonadState' s m => 'Getting' r s t a b -> (a -> r) -> m r</span>
<a name="line-361"></a><span class='hs-comment'>-- @</span>
<a name="line-362"></a><span class='hs-definition'>uses</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadState</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>LensLike'</span> <span class='hs-layout'>(</span><span class='hs-conid'>Const</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span>
<a name="line-363"></a><span class='hs-definition'>uses</span> <span class='hs-varid'>l</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>State</span><span class='hs-varop'>.</span><span class='hs-varid'>gets</span> <span class='hs-layout'>(</span><span class='hs-varid'>views</span> <span class='hs-varid'>l</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span>
<a name="line-364"></a><span class='hs-comment'>{-# INLINE uses #-}</span>
<a name="line-365"></a>
<a name="line-366"></a><a name="listening"></a><span class='hs-comment'>-- | This is a generalized form of 'listen' that only extracts the portion of</span>
<a name="line-367"></a><span class='hs-comment'>-- the log that is focused on by a 'Getter'. If given a 'Fold' or a 'Traversal'</span>
<a name="line-368"></a><span class='hs-comment'>-- then a monoidal summary of the parts of the log that are visited will be</span>
<a name="line-369"></a><span class='hs-comment'>-- returned.</span>
<a name="line-370"></a><span class='hs-comment'>--</span>
<a name="line-371"></a><span class='hs-comment'>-- @</span>
<a name="line-372"></a><span class='hs-comment'>-- 'listening' :: 'MonadWriter' w m => 'Getter' w u -> m a -> m (a, u)</span>
<a name="line-373"></a><span class='hs-comment'>-- 'listening' :: 'MonadWriter' w m => 'Lens'' w u -> m a -> m (a, u)</span>
<a name="line-374"></a><span class='hs-comment'>-- 'listening' :: 'MonadWriter' w m => 'Iso'' w u -> m a -> m (a, u)</span>
<a name="line-375"></a><span class='hs-comment'>-- 'listening' :: ('MonadWriter' w m, 'Monoid' u) => 'Fold' w u -> m a -> m (a, u)</span>
<a name="line-376"></a><span class='hs-comment'>-- 'listening' :: ('MonadWriter' w m, 'Monoid' u) => 'Traversal'' w u -> m a -> m (a, u)</span>
<a name="line-377"></a><span class='hs-comment'>-- 'listening' :: ('MonadWriter' w m, 'Monoid' u) => 'Prism'' w u -> m a -> m (a, u)</span>
<a name="line-378"></a><span class='hs-comment'>-- @</span>
<a name="line-379"></a><span class='hs-definition'>listening</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadWriter</span> <span class='hs-varid'>w</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Getting</span> <span class='hs-varid'>u</span> <span class='hs-varid'>w</span> <span class='hs-varid'>u</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>u</span><span class='hs-layout'>)</span>
<a name="line-380"></a><span class='hs-definition'>listening</span> <span class='hs-varid'>l</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-381"></a> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>listen</span> <span class='hs-varid'>m</span>
<a name="line-382"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>view</span> <span class='hs-varid'>l</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-383"></a><span class='hs-comment'>{-# INLINE listening #-}</span>
<a name="line-384"></a>
<a name="line-385"></a><a name="ilistening"></a><span class='hs-comment'>-- | This is a generalized form of 'listen' that only extracts the portion of</span>
<a name="line-386"></a><span class='hs-comment'>-- the log that is focused on by a 'Getter'. If given a 'Fold' or a 'Traversal'</span>
<a name="line-387"></a><span class='hs-comment'>-- then a monoidal summary of the parts of the log that are visited will be</span>
<a name="line-388"></a><span class='hs-comment'>-- returned.</span>
<a name="line-389"></a><span class='hs-comment'>--</span>
<a name="line-390"></a><span class='hs-comment'>-- @</span>
<a name="line-391"></a><span class='hs-comment'>-- 'ilistening' :: 'MonadWriter' w m => 'IndexedGetter' i w u -> m a -> m (a, (i, u))</span>
<a name="line-392"></a><span class='hs-comment'>-- 'ilistening' :: 'MonadWriter' w m => 'IndexedLens'' i w u -> m a -> m (a, (i, u))</span>
<a name="line-393"></a><span class='hs-comment'>-- 'ilistening' :: ('MonadWriter' w m, 'Monoid' u) => 'IndexedFold' i w u -> m a -> m (a, (i, u))</span>
<a name="line-394"></a><span class='hs-comment'>-- 'ilistening' :: ('MonadWriter' w m, 'Monoid' u) => 'IndexedTraversal'' i w u -> m a -> m (a, (i, u))</span>
<a name="line-395"></a><span class='hs-comment'>-- @</span>
<a name="line-396"></a><span class='hs-definition'>ilistening</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadWriter</span> <span class='hs-varid'>w</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>IndexedGetting</span> <span class='hs-varid'>i</span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span><span class='hs-layout'>,</span> <span class='hs-varid'>u</span><span class='hs-layout'>)</span> <span class='hs-varid'>w</span> <span class='hs-varid'>u</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span><span class='hs-layout'>,</span> <span class='hs-varid'>u</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-397"></a><span class='hs-definition'>ilistening</span> <span class='hs-varid'>l</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-398"></a> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>listen</span> <span class='hs-varid'>m</span>
<a name="line-399"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>iview</span> <span class='hs-varid'>l</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-400"></a><span class='hs-comment'>{-# INLINE ilistening #-}</span>
<a name="line-401"></a>
<a name="line-402"></a><a name="listenings"></a><span class='hs-comment'>-- | This is a generalized form of 'listen' that only extracts the portion of</span>
<a name="line-403"></a><span class='hs-comment'>-- the log that is focused on by a 'Getter'. If given a 'Fold' or a 'Traversal'</span>
<a name="line-404"></a><span class='hs-comment'>-- then a monoidal summary of the parts of the log that are visited will be</span>
<a name="line-405"></a><span class='hs-comment'>-- returned.</span>
<a name="line-406"></a><span class='hs-comment'>--</span>
<a name="line-407"></a><span class='hs-comment'>-- @</span>
<a name="line-408"></a><span class='hs-comment'>-- 'listenings' :: 'MonadWriter' w m => 'Getter' w u -> (u -> v) -> m a -> m (a, v)</span>
<a name="line-409"></a><span class='hs-comment'>-- 'listenings' :: 'MonadWriter' w m => 'Lens'' w u -> (u -> v) -> m a -> m (a, v)</span>
<a name="line-410"></a><span class='hs-comment'>-- 'listenings' :: 'MonadWriter' w m => 'Iso'' w u -> (u -> v) -> m a -> m (a, v)</span>
<a name="line-411"></a><span class='hs-comment'>-- 'listenings' :: ('MonadWriter' w m, 'Monoid' v) => 'Fold' w u -> (u -> v) -> m a -> m (a, v)</span>
<a name="line-412"></a><span class='hs-comment'>-- 'listenings' :: ('MonadWriter' w m, 'Monoid' v) => 'Traversal'' w u -> (u -> v) -> m a -> m (a, v)</span>
<a name="line-413"></a><span class='hs-comment'>-- 'listenings' :: ('MonadWriter' w m, 'Monoid' v) => 'Prism'' w u -> (u -> v) -> m a -> m (a, v)</span>
<a name="line-414"></a><span class='hs-comment'>-- @</span>
<a name="line-415"></a><span class='hs-definition'>listenings</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadWriter</span> <span class='hs-varid'>w</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Getting</span> <span class='hs-varid'>v</span> <span class='hs-varid'>w</span> <span class='hs-varid'>u</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>u</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span>
<a name="line-416"></a><span class='hs-definition'>listenings</span> <span class='hs-varid'>l</span> <span class='hs-varid'>uv</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-417"></a> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>listen</span> <span class='hs-varid'>m</span>
<a name="line-418"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>views</span> <span class='hs-varid'>l</span> <span class='hs-varid'>uv</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-419"></a><span class='hs-comment'>{-# INLINE listenings #-}</span>
<a name="line-420"></a>
<a name="line-421"></a><a name="ilistenings"></a><span class='hs-comment'>-- | This is a generalized form of 'listen' that only extracts the portion of</span>
<a name="line-422"></a><span class='hs-comment'>-- the log that is focused on by a 'Getter'. If given a 'Fold' or a 'Traversal'</span>
<a name="line-423"></a><span class='hs-comment'>-- then a monoidal summary of the parts of the log that are visited will be</span>
<a name="line-424"></a><span class='hs-comment'>-- returned.</span>
<a name="line-425"></a><span class='hs-comment'>--</span>
<a name="line-426"></a><span class='hs-comment'>-- @</span>
<a name="line-427"></a><span class='hs-comment'>-- 'ilistenings' :: 'MonadWriter' w m => 'IndexedGetter' w u -> (i -> u -> v) -> m a -> m (a, v)</span>
<a name="line-428"></a><span class='hs-comment'>-- 'ilistenings' :: 'MonadWriter' w m => 'IndexedLens'' w u -> (i -> u -> v) -> m a -> m (a, v)</span>
<a name="line-429"></a><span class='hs-comment'>-- 'ilistenings' :: ('MonadWriter' w m, 'Monoid' v) => 'IndexedFold' w u -> (i -> u -> v) -> m a -> m (a, v)</span>
<a name="line-430"></a><span class='hs-comment'>-- 'ilistenings' :: ('MonadWriter' w m, 'Monoid' v) => 'IndexedTraversal'' w u -> (i -> u -> v) -> m a -> m (a, v)</span>
<a name="line-431"></a><span class='hs-comment'>-- @</span>
<a name="line-432"></a><span class='hs-definition'>ilistenings</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadWriter</span> <span class='hs-varid'>w</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>IndexedGetting</span> <span class='hs-varid'>i</span> <span class='hs-varid'>v</span> <span class='hs-varid'>w</span> <span class='hs-varid'>u</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>u</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span>
<a name="line-433"></a><span class='hs-definition'>ilistenings</span> <span class='hs-varid'>l</span> <span class='hs-varid'>iuv</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-434"></a> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>listen</span> <span class='hs-varid'>m</span>
<a name="line-435"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>iviews</span> <span class='hs-varid'>l</span> <span class='hs-varid'>iuv</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-436"></a><span class='hs-comment'>{-# INLINE ilistenings #-}</span>
<a name="line-437"></a>
<a name="line-438"></a><span class='hs-comment'>------------------------------------------------------------------------------</span>
<a name="line-439"></a><span class='hs-comment'>-- Indexed Getters</span>
<a name="line-440"></a><span class='hs-comment'>------------------------------------------------------------------------------</span>
<a name="line-441"></a>
<a name="line-442"></a><a name="iview"></a><span class='hs-comment'>-- | View the index and value of an 'IndexedGetter' into the current environment as a pair.</span>
<a name="line-443"></a><span class='hs-comment'>--</span>
<a name="line-444"></a><span class='hs-comment'>-- When applied to an 'IndexedFold' the result will most likely be a nonsensical monoidal summary of</span>
<a name="line-445"></a><span class='hs-comment'>-- the indices tupled with a monoidal summary of the values and probably not whatever it is you wanted.</span>
<a name="line-446"></a><span class='hs-definition'>iview</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadReader</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>IndexedGetting</span> <span class='hs-varid'>i</span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span><span class='hs-layout'>,</span><span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span><span class='hs-layout'>,</span><span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-447"></a><span class='hs-definition'>iview</span> <span class='hs-varid'>l</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>asks</span> <span class='hs-layout'>(</span><span class='hs-varid'>getConst</span> <span class='hs-cpp'>#.</span> <span class='hs-varid'>l</span> <span class='hs-layout'>(</span><span class='hs-conid'>Indexed</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>i</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Const</span> <span class='hs-cpp'>#.</span> <span class='hs-conid'>(,)</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-448"></a><span class='hs-comment'>{-# INLINE iview #-}</span>
<a name="line-449"></a>
<a name="line-450"></a><a name="iviews"></a><span class='hs-comment'>-- | View a function of the index and value of an 'IndexedGetter' into the current environment.</span>
<a name="line-451"></a><span class='hs-comment'>--</span>
<a name="line-452"></a><span class='hs-comment'>-- When applied to an 'IndexedFold' the result will be a monoidal summary instead of a single answer.</span>
<a name="line-453"></a><span class='hs-comment'>--</span>
<a name="line-454"></a><span class='hs-comment'>-- @</span>
<a name="line-455"></a><span class='hs-comment'>-- 'iviews' ≡ 'Control.Lens.Fold.ifoldMapOf'</span>
<a name="line-456"></a><span class='hs-comment'>-- @</span>
<a name="line-457"></a><span class='hs-definition'>iviews</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadReader</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>IndexedGetting</span> <span class='hs-varid'>i</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span>
<a name="line-458"></a><span class='hs-definition'>iviews</span> <span class='hs-varid'>l</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>asks</span> <span class='hs-layout'>(</span><span class='hs-varid'>getConst</span> <span class='hs-cpp'>#.</span> <span class='hs-varid'>l</span> <span class='hs-layout'>(</span><span class='hs-conid'>Const</span> <span class='hs-cpp'>#.</span> <span class='hs-conid'>Indexed</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-459"></a><span class='hs-comment'>{-# INLINE iviews #-}</span>
<a name="line-460"></a>
<a name="line-461"></a><a name="iuse"></a><span class='hs-comment'>-- | Use the index and value of an 'IndexedGetter' into the current state as a pair.</span>
<a name="line-462"></a><span class='hs-comment'>--</span>
<a name="line-463"></a><span class='hs-comment'>-- When applied to an 'IndexedFold' the result will most likely be a nonsensical monoidal summary of</span>
<a name="line-464"></a><span class='hs-comment'>-- the indices tupled with a monoidal summary of the values and probably not whatever it is you wanted.</span>
<a name="line-465"></a><span class='hs-definition'>iuse</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadState</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>IndexedGetting</span> <span class='hs-varid'>i</span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span><span class='hs-layout'>,</span><span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span><span class='hs-layout'>,</span><span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-466"></a><span class='hs-definition'>iuse</span> <span class='hs-varid'>l</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>gets</span> <span class='hs-layout'>(</span><span class='hs-varid'>getConst</span> <span class='hs-cpp'>#.</span> <span class='hs-varid'>l</span> <span class='hs-layout'>(</span><span class='hs-conid'>Indexed</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>i</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Const</span> <span class='hs-cpp'>#.</span> <span class='hs-conid'>(,)</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-467"></a><span class='hs-comment'>{-# INLINE iuse #-}</span>
<a name="line-468"></a>
<a name="line-469"></a><a name="iuses"></a><span class='hs-comment'>-- | Use a function of the index and value of an 'IndexedGetter' into the current state.</span>
<a name="line-470"></a><span class='hs-comment'>--</span>
<a name="line-471"></a><span class='hs-comment'>-- When applied to an 'IndexedFold' the result will be a monoidal summary instead of a single answer.</span>
<a name="line-472"></a><span class='hs-definition'>iuses</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadState</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>IndexedGetting</span> <span class='hs-varid'>i</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span>
<a name="line-473"></a><span class='hs-definition'>iuses</span> <span class='hs-varid'>l</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>gets</span> <span class='hs-layout'>(</span><span class='hs-varid'>getConst</span> <span class='hs-cpp'>#.</span> <span class='hs-varid'>l</span> <span class='hs-layout'>(</span><span class='hs-conid'>Const</span> <span class='hs-cpp'>#.</span> <span class='hs-conid'>Indexed</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-474"></a><span class='hs-comment'>{-# INLINE iuses #-}</span>
<a name="line-475"></a>
<a name="line-476"></a><a name="%5e@."></a><span class='hs-comment'>-- | View the index and value of an 'IndexedGetter' or 'IndexedLens'.</span>
<a name="line-477"></a><span class='hs-comment'>--</span>
<a name="line-478"></a><span class='hs-comment'>-- This is the same operation as 'iview' with the arguments flipped.</span>
<a name="line-479"></a><span class='hs-comment'>--</span>
<a name="line-480"></a><span class='hs-comment'>-- The fixity and semantics are such that subsequent field accesses can be</span>
<a name="line-481"></a><span class='hs-comment'>-- performed with ('Prelude..').</span>
<a name="line-482"></a><span class='hs-comment'>--</span>
<a name="line-483"></a><span class='hs-comment'>-- @</span>
<a name="line-484"></a><span class='hs-comment'>-- ('^@.') :: s -> 'IndexedGetter' i s a -> (i, a)</span>
<a name="line-485"></a><span class='hs-comment'>-- ('^@.') :: s -> 'IndexedLens'' i s a -> (i, a)</span>
<a name="line-486"></a><span class='hs-comment'>-- @</span>
<a name="line-487"></a><span class='hs-comment'>--</span>
<a name="line-488"></a><span class='hs-comment'>-- The result probably doesn't have much meaning when applied to an 'IndexedFold'.</span>
<a name="line-489"></a><span class='hs-layout'>(</span><span class='hs-varop'>^@.</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IndexedGetting</span> <span class='hs-varid'>i</span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span><span class='hs-layout'>,</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span><span class='hs-layout'>,</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-490"></a><span class='hs-definition'>s</span> <span class='hs-varop'>^@.</span> <span class='hs-varid'>l</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>getConst</span> <span class='hs-varop'>$</span> <span class='hs-varid'>l</span> <span class='hs-layout'>(</span><span class='hs-conid'>Indexed</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>i</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Const</span> <span class='hs-cpp'>#.</span> <span class='hs-conid'>(,)</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-varid'>s</span>
<a name="line-491"></a><span class='hs-comment'>{-# INLINE (^@.) #-}</span>
<a name="line-492"></a>
<a name="line-493"></a><a name="getting"></a><span class='hs-comment'>-- | Coerce a 'Getter'-compatible 'LensLike' to a 'LensLike''. This</span>
<a name="line-494"></a><span class='hs-comment'>-- is useful when using a 'Traversal' that is not simple as a 'Getter' or a</span>
<a name="line-495"></a><span class='hs-comment'>-- 'Fold'.</span>
<a name="line-496"></a><span class='hs-definition'>getting</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Functor</span> <span class='hs-varid'>f</span><span class='hs-layout'>,</span> <span class='hs-conid'>Contravariant</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>LensLike</span> <span class='hs-varid'>f</span> <span class='hs-varid'>s</span> <span class='hs-varid'>t</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>LensLike'</span> <span class='hs-varid'>f</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span>
<a name="line-497"></a><span class='hs-definition'>getting</span> <span class='hs-varid'>l</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>phantom</span> <span class='hs-varop'>.</span> <span class='hs-varid'>l</span> <span class='hs-layout'>(</span><span class='hs-varid'>phantom</span> <span class='hs-varop'>.</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span>
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