Merge pull request #105 from dwhitney/master

added toArrayOf and toArrayOfOn

Author: thomashoneyman

src/Data/Lens.purs

@@ -31,5 +31,5 @@ import Data.Lens.Traversal (Traversal, Traversal', element, elementsOf, failover
 import Data.Lens.Types (class Wander, ALens, ALens', APrism, APrism', AnIso, AnIso', Fold, Fold', Getter, Getter', AGetter, AGetter', IndexedFold, IndexedFold', IndexedGetter, IndexedGetter', IndexedOptic, IndexedOptic', IndexedSetter, IndexedSetter', IndexedTraversal, IndexedTraversal', Iso, Iso', Lens, Lens', Optic, Optic', Prism, Prism', Review, Review', Setter, Setter', Traversal, Traversal', Exchange(..), Forget(..), Indexed(..), Market(..), Re(..), Shop(..), Tagged(..), wander)
 import Data.Lens.Setter (IndexedSetter, Setter, Setter', Indexed(..), addModifying, addOver, appendModifying, appendOver, assign, assignJust, conjModifying, conjOver, disjModifying, disjOver, divModifying, divOver, iover, modifying, mulModifying, mulOver, over, set, setJust, subModifying, subOver, (%=), (%~), (&&=), (&&~), (*=), (*~), (++=), (++~), (+=), (+~), (-=), (-~), (.=), (.~), (//=), (//~), (<>=), (<>~), (?=), (?~), (||=), (||~))
 import Data.Lens.Getter (Fold, Getter, IndexedFold, IndexedGetter, Optic, Indexed(..), iuse, iview, to, takeBoth, use, view, viewOn, (^.), cloneGetter)
-import Data.Lens.Fold (Fold, Fold', allOf, andOf, anyOf, elemOf, filtered, findOf, firstOf, foldMapOf, foldOf, folded, foldlOf, foldrOf, has, hasn't, iallOf, ianyOf, ifoldMapOf, ifoldlOf, ifoldrOf, itoListOf, itraverseOf_, lastOf, lengthOf, maximumOf, minimumOf, notElemOf, orOf, preview, previewOn, productOf, replicated, sequenceOf_, sumOf, toListOf, toListOfOn, unfolded, (^..), (^?))
+import Data.Lens.Fold (Fold, Fold', allOf, andOf, anyOf, elemOf, filtered, findOf, firstOf, foldMapOf, foldOf, folded, foldlOf, foldrOf, has, hasn't, iallOf, ianyOf, ifoldMapOf, ifoldlOf, ifoldrOf, itoListOf, itraverseOf_, lastOf, lengthOf, maximumOf, minimumOf, notElemOf, orOf, preview, previewOn, productOf, replicated, sequenceOf_, sumOf, toArrayOf, toArrayOfOn, toListOf, toListOfOn, unfolded, (^..), (^?))
 import Data.Lens.Common (_1, _2, _Just, _Left, _Nothing, _Right, first, left, right, second, united)

src/Data/Lens/Fold.purs

@@ -5,14 +5,15 @@ module Data.Lens.Fold
   , preview, foldOf, foldMapOf, foldrOf, foldlOf, toListOf, firstOf, lastOf
   , maximumOf, minimumOf, allOf, anyOf, andOf, orOf, elemOf, notElemOf, sumOf
   , productOf, lengthOf, findOf, sequenceOf_, traverseOf_, has, hasn't
-  , replicated, filtered, folded, unfolded
+  , replicated, filtered, folded, unfolded, toArrayOf, toArrayOfOn
   , ifoldMapOf, ifoldrOf, ifoldlOf, iallOf, ianyOf, itoListOf, itraverseOf_
   , module ExportTypes
   )
   where
 
 import Prelude
 
+import Data.Array (fromFoldable) as Array
 import Data.Either (Either(..), either)
 import Data.Foldable (class Foldable, foldMap)
 import Data.HeytingAlgebra (tt, ff)
@@ -148,6 +149,15 @@ toListOfOn s p = toListOf p s
 
 infixl 8 toListOfOn as ^..
 
+-- | Collects the foci of a `Fold` into an array.
+toArrayOf :: forall s t a b. Fold (Endo (->) (List a)) s t a b -> s -> Array a
+toArrayOf p = Array.fromFoldable <<< toListOf p
+
+-- | Synonym for `toArrayOf`, reversed.
+toArrayOfOn :: forall s t a b. s -> Fold (Endo (->) (List a)) s t a b -> Array a
+toArrayOfOn s p = toArrayOf p s
+
+
 -- | Determines whether a `Fold` has at least one focus.
 has :: forall s t a b r. HeytingAlgebra r => Fold (Disj r) s t a b -> s -> r
 has p = unwrap <<< foldMapOf p (const (Disj tt))

test/Main.purs

@@ -5,7 +5,7 @@ import Prelude
 import Control.Monad.State (evalState, get)
 import Data.Distributive (class Distributive)
 import Data.Either (Either(..))
-import Data.Lens (Getter', _1, _2, _Just, _Left, collectOf, lens, preview, takeBoth, traversed, view)
+import Data.Lens (Getter', Prism', _1, _2, _Just, _Left, collectOf, lens, preview, prism', takeBoth, toArrayOf, traversed, view)
 import Data.Lens.Fold ((^?))
 import Data.Lens.Fold.Partial ((^?!), (^@?!))
 import Data.Lens.Grate (Grate, cloneGrate, grate, zipWithOf)
@@ -39,6 +39,23 @@ fooGetter = foo
 barGetter :: forall x. Getter' { bar :: x } x
 barGetter = bar
 
+-- testing toArrayOf with traversed and a couple of prisms
+data ABC = A (Array XYZ) | B | C
+data XYZ = X Number | Y | Z
+
+_A :: Prism' ABC (Array XYZ)
+_A = prism' A case _ of 
+  (A array) -> Just array
+  _ -> Nothing
+
+_X :: Prism' XYZ Number
+_X = prism' X case _ of
+  (X number) -> Just number
+  _ -> Nothing
+
+arrayOfNumbers :: ABC -> Array Number
+arrayOfNumbers = toArrayOf (_A <<< traversed <<< _X)
+
 -- check we can compose getters
 fooBarGetter :: forall x. Getter' { foo :: { bar :: x } } x
 fooBarGetter = foo <<< bar
@@ -109,6 +126,7 @@ main = do
   logShow $ view bars doc
   logShow $ view barAndFoo { bar: "bar", foo: "foo" }
   logShow $ doc2 ^? _1bars
+  logShow $ arrayOfNumbers $ A [(X 1.0), (X 2.0), (X 3.0)]
   logShow $ unsafePartial $ doc2 ^?! _1bars
   logShow $ unsafePartial $ Tuple 0 1 ^@?! i_2
   logShow stateTest