lens 3.0.3 → 3.0.4

raw patch · 4 files changed

+78/−7 lines, 4 files

Files

• CHANGELOG.markdown +4/−0
• lens.cabal +1/−1
• src/Control/Lens/IndexedLens.hs +1/−1
• src/Control/Lens/Setter.hs +72/−5

@@ -1,3 +1,7 @@+3.0.4+-----+* Added `?~`, `<?~`, `?=` and `<?=` to `Control.Lens.Setter` for setting the target(s) of a Lens to `Just` a value. They are particularly useful when combined with `at`.+ 3.0.3 ----- * Refined the behavior of `substType` in `Control.Lens.TH` to match the behavior of `typeVarsEx` when moving under binders.

@@ -1,6 +1,6 @@ name:          lens category:      Data, Lenses-version:       3.0.3+version:       3.0.4 license:       BSD3 cabal-version: >= 1.8 license-file:  LICENSE

@@ -143,7 +143,7 @@   -- >>> Map.fromList [(1,"hello")] ^.at 1   -- Just "hello"   ---  -- >>> at 1 .~ Just "hello" $ Map.empty+  -- >>> at 1 ?~ "hello" $ Map.empty   -- fromList [(1,"hello")]   at :: k -> SimpleIndexedLens k (m v) (Maybe v) 

@@ -34,11 +34,11 @@   , mapOf   , set   , (.~), (%~)-  , (+~), (-~), (*~), (//~), (^~), (^^~), (**~), (||~), (&&~), (<.~)+  , (+~), (-~), (*~), (//~), (^~), (^^~), (**~), (||~), (&&~), (<.~), (?~), (<?~)   -- * State Combinators   , assign   , (.=), (%=)-  , (+=), (-=), (*=), (//=), (^=), (^^=), (**=), (||=), (&&=), (<.=)+  , (+=), (-=), (*=), (//=), (^=), (^^=), (**=), (||=), (&&=), (<.=), (?=), (<?=)   , (<~)   -- * Storing Setters   , ReifiedSetter(..)@@ -60,8 +60,8 @@ -- $setup -- >>> import Control.Lens -infixr 4 .~, +~, *~, -~, //~, ^~, ^^~, **~, &&~, ||~, %~, <.~-infix  4 .=, +=, *=, -=, //=, ^=, ^^=, **=, &&=, ||=, %=, <.=+infixr 4 .~, +~, *~, -~, //~, ^~, ^^~, **~, &&~, ||~, %~, <.~, ?~, <?~+infix  4 .=, +=, *=, -=, //=, ^=, ^^=, **=, &&=, ||=, %=, <.=, ?=, <?= infixr 2 <~  ------------------------------------------------------------------------------@@ -304,6 +304,20 @@ (.~) = set {-# INLINE (.~) #-} +-- | Set the target of a 'Control.Lens.Type.Lens', 'Control.Lens.Traversal.Traversal' or 'Setter' to 'Just' a value.+--+-- @l '?~' d ≡ 'set' l ('Just' d)@+--+-- @+-- ('?~') :: 'Setter' a b c ('Maybe' d)    -> d -> a -> b+-- ('?~') :: 'Control.Lens.Iso.Iso' a b c ('Maybe' d)       -> d -> a -> b+-- ('?~') :: 'Control.Lens.Type.Lens' a b c ('Maybe' d)      -> d -> a -> b+-- ('?~') :: 'Control.Lens.Traversal.Traversal' a b c ('Maybe' d) -> d -> a -> b+-- @+(?~) :: Setting a b c (Maybe d) -> d -> a -> b+l ?~ d = set l (Just d)+{-# INLINE (?~) #-}+ -- | Set with pass-through -- -- This is mostly present for consistency, but may be useful for for chaining assignments@@ -324,9 +338,29 @@ -- ('<.~') :: 'Control.Lens.Traversal.Traversal' a b c d -> d -> a -> (d, b) -- @ (<.~) :: Setting a b c d -> d -> a -> (d, b)-l <.~ d = \a -> (d, l .~ d $ a)+l <.~ d = \a -> (d, set l d a) {-# INLINE (<.~) #-} +-- | Set to 'Just' a value with pass-through+--+-- This is mostly present for consistency, but may be useful for for chaining assignments+--+-- If you do not need a copy of the intermediate result, then using @l '?~' d@ directly is a good idea.+--+-- >>> import Data.Map as Map+-- >>> _2.at "hello" <?~ "world" $ (42,Map.fromList [("goodnight","gracie")])+-- ("world",(42,fromList [("goodnight","gracie"),("hello","world")]))+--+-- @+-- ('<?~') :: 'Setter' a b c d    -> ('Maybe' d) -> a -> (d, b)+-- ('<?~') :: 'Control.Lens.Iso.Iso' a b c ('Maybe' d)       -> d -> a -> (d, b)+-- ('<?~') :: 'Control.Lens.Type.Lens' a b c ('Maybe' d)      -> d -> a -> (d, b)+-- ('<?~') :: 'Control.Lens.Traversal.Traversal' a b c ('Maybe' d) -> d -> a -> (d, b)+-- @+(<?~) :: Setting a b c (Maybe d) -> d -> a -> (d, b)+l <?~ d = \a -> (d, set l (Just d) a)+{-# INLINE (<?~) #-}+ -- | Increment the target(s) of a numerically valued 'Control.Lens.Type.Lens', 'Setter' or 'Control.Lens.Traversal.Traversal' -- -- >>> _1 +~ 1 $ (1,2)@@ -525,6 +559,19 @@ l %= f = State.modify (l %~ f) {-# INLINE (%=) #-} +-- | Replace the target of a 'Control.Lens.Type.Lens' or all of the targets of a 'Setter' or 'Control.Lens.Traversal.Traversal' in our monadic+-- state with 'Just' a new value, irrespective of the old.+--+-- @+-- ('?=') :: 'MonadState' a m => 'Control.Lens.Type.Simple' 'Control.Lens.Iso.Iso' a ('Maybe' b)       -> b -> m ()+-- ('?=') :: 'MonadState' a m => 'Control.Lens.Type.Simple' 'Control.Lens.Type.Lens' a ('Maybe' b)      -> b -> m ()+-- ('?=') :: 'MonadState' a m => 'Control.Lens.Type.Simple' 'Control.Lens.Traversal.Traversal' a ('Maybe' b) -> b -> m ()+-- ('?=') :: 'MonadState' a m => 'Control.Lens.Type.Simple' 'Setter' a ('Maybe' b)    -> b -> m ()+-- @+(?=) :: MonadState a m => Setting a a c (Maybe d) -> d -> m ()+l ?= b = State.modify (l ?~ b)+{-# INLINE (?=) #-}+ -- | Modify the target(s) of a 'Control.Lens.Type.Simple' 'Control.Lens.Type.Lens', 'Control.Lens.Iso.Iso', 'Setter' or 'Control.Lens.Traversal.Traversal' by adding a value -- -- Example:@@ -690,6 +737,26 @@   l .= d   return d {-# INLINE (<.=) #-}++-- | Set 'Just' a value with pass-through+--+-- This is useful for chaining assignment without round-tripping through your monad stack.+--+-- @do x <- at "foo" <?= ninety_nine_bottles_of_beer_on_the_wall@+--+-- If you do not need a copy of the intermediate result, then using @l ?= d@ will avoid unused binding warnings+--+-- @+-- ('<?=') :: 'MonadState' a m => 'Setter' a a c ('Maybe' d) -> d -> m d+-- ('<?=') :: 'MonadState' a m => 'Control.Lens.Iso.Iso' a a c ('Maybe' d) -> d -> m d+-- ('<?=') :: 'MonadState' a m => 'Control.Lens.Type.Lens' a a c ('Maybe' d) -> d -> m d+-- ('<?=') :: 'MonadState' a m => 'Control.Lens.Traversal.Traversal' a a c ('Maybe' d) -> d -> m d+-- @+(<?=) :: MonadState a m => Setting a a c (Maybe d) -> d -> m d+l <?= d = do+  l ?= d+  return d+{-# INLINE (<?=) #-}  -- | Reify a setter so it can be stored safely in a container. newtype ReifiedSetter a b c d = ReifySetter { reflectSetter :: Setter a b c d }