data-lens-template 2.0 → 2.1.0

raw patch · 2 files changed

+25/−22 lines, 2 files

Files

• Data/Lens/Template.hs +24/−21
• data-lens-template.cabal +1/−1

@@ -6,53 +6,56 @@ accessor objects for them automatically. -} module Data.Lens.Template (-   nameDeriveAccessors, deriveAccessors,+   nameMakeLens, makeLenses, makeLens,    ) where  import Language.Haskell.TH.Syntax-import Control.Monad (liftM, when)+import Control.Monad (liftM, when, (<=<)) import Data.Maybe (catMaybes) import Data.List (nub) import Data.Lens.Common --- |@deriveAccessors n@ where @n@ is the name of a data type+-- |@makeLenses n@ where @n@ is the name of a data type -- declared with @data@ looks through all the declared fields--- of the data type, and for each field ending in an underscore+-- of the data type, and for each field beginning with an underscore -- generates an accessor of the same name without the underscore. ----- It is "nameDeriveAccessors" n f where @f@ satisfies+-- It is "nameMakeLens" n f where @f@ satisfies ----- > f (s ++ "_") = Just s+-- > f ('_' : s) = Just s -- > f x = Nothing -- otherwise -- -- For example, given the data type: -- -- > data Score = Score { --- >   p1Score_ :: Int--- > , p2Score_ :: Int+-- >   _p1Score :: Int+-- > , _p2Score :: Int -- > , rounds :: Int -- > } ----- @deriveAccessors@ will generate the following objects:+-- @makeLenses@ will generate the following objects: -- -- > p1Score :: Lens Score Int--- > p1Score = lens p1Score_ (\x s -> s { p1Score_ = x })+-- > p1Score = lens _p1Score (\x s -> s { _p1Score = x }) -- > p2Score :: Lens Score Int--- > p2Score = lens p2Score_ (\x s -> s { p2Score_ = x })+-- > p2Score = lens _p2Score (\x s -> s { _p2Score = x }) -- -- It is used with Template Haskell syntax like: ----- > $( deriveAccessors ''TypeName )+-- > $( makeLenses ''TypeName ) -- -- And will generate accessors when TypeName was declared -- using @data@ or @newtype@.-deriveAccessors :: Name -> Q [Dec]-deriveAccessors n = nameDeriveAccessors n stripUnderscore+makeLenses :: [Name] -> Q [Dec]+makeLenses = return . concat <=< mapM makeLens +makeLens :: Name -> Q [Dec]+makeLens n = nameMakeLens n stripUnderscore+ stripUnderscore :: String -> Maybe String stripUnderscore [] = Nothing stripUnderscore s -   | last s == '_' = Just (init s)+   | head s == '_' = Just (tail s)    | otherwise = Nothing  namedFields :: Con -> [VarStrictType]@@ -60,13 +63,13 @@ namedFields (ForallC _ _ c) = namedFields c namedFields _ = [] --- |@nameDeriveAccessors n f@ where @n@ is the name of a data type+-- |@nameMakeLens n f@ where @n@ is the name of a data type -- declared with @data@ and @f@ is a function from names of fields -- in that data type to the name of the corresponding accessor. If -- @f@ returns @Nothing@, then no accessor is generated for that -- field.-nameDeriveAccessors :: Name -> (String -> Maybe String) -> Q [Dec]-nameDeriveAccessors t namer = do+nameMakeLens :: Name -> (String -> Maybe String) -> Q [Dec]+nameMakeLens t namer = do     info <- reify t     reified <- case info of                     TyConI dec -> return dec@@ -84,11 +87,11 @@     errmsg = "Cannot derive accessors for name " ++ show t ++ " because"           ++ "\n it is not a type declared with 'data' or 'newtype'"           ++ "\n Did you remember to double-tick the type as in"-          ++ "\n $(deriveAccessors ''TheType)?"+          ++ "\n $(makeLenses ''TheType)?"      nodefmsg = "Warning: No accessors generated from the name " ++ show t-          ++ "\n If you are using deriveAccessors rather than"-          ++ "\n nameDeriveAccessors, remember accessors are"+          ++ "\n If you are using makeLenses rather than"+          ++ "\n nameMakeLens, remember accessors are"           ++ "\n only generated for fields ending with an underscore"      makeAccs :: [TyVarBndr] -> [VarStrictType] -> Q [Dec]

@@ -1,5 +1,5 @@ name:          data-lens-template-version:       2.0+version:       2.1.0 license:       BSD3 license-file:  LICENSE author:        Joel Burget <joelburget@gmail.com>