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1. mapExceptT :: (m (Either e a) -> n (Either e' b)) -> ExceptT e m a -> ExceptT e' n b

   can-i-haz	Control.Monad.Except.CoHas

   Map the unwrapped computation using the given function.

   • runExceptT (mapExceptT f m) = f
     (runExceptT m)

2. mapReader :: (a -> b) -> Reader r a -> Reader r b

   can-i-haz	Control.Monad.Reader.Has

   Transform the value returned by a Reader.

   • runReader (mapReader f m) = f .
     runReader m

3. mapReaderT :: (m a -> n b) -> ReaderT r m a -> ReaderT r n b

   can-i-haz	Control.Monad.Reader.Has

   Transform the computation inside a ReaderT.

   • runReaderT (mapReaderT f m) = f .
     runReaderT m

4. mapMaybeVarEnv :: (a -> Maybe b) -> VarEnv a -> VarEnv b

   clash-lib	Clash.Core.VarEnv

   Apply a function to every element in the environment; values for which the function returns Nothing are removed from the environment

5. mapVarEnv :: (a -> b) -> VarEnv a -> VarEnv b

   clash-lib	Clash.Core.VarEnv

   Apply a function to every element in the environment

6. mapMaybe :: (a -> Maybe b) -> UniqMap a -> UniqMap b

   clash-lib	Clash.Data.UniqMap

   Apply a function to all elements in the map, keeping those where the result is not Nothing.

7. map' :: Expr -> Expr -> Expr

   code-conjure	Conjure.Engine

   map lifted over Exprs.

   > map' absE (unit one)
   map abs [1] :: [Int]
   

8. mapConsts :: (Expr -> Expr) -> Expr -> Expr

   code-conjure	Conjure.Engine

   O(n*m). Applies a function to all terminal constants in an expression. Given that:

   > let one   = val (1 :: Int)
   > let two   = val (2 :: Int)
   > let xx -+- yy = value "+" ((+) :: Int->Int->Int) :$ xx :$ yy
   > let intToZero e = if typ e == typ zero then zero else e
   

   Then:

   > one -+- (two -+- xx)
   1 + (2 + x) :: Int
   

   > mapConsts intToZero (one -+- (two -+- xx))
   0 + (0 + x) :: Integer
   

   Given that the argument function is O(m), this function is O(n*m).

9. mapE :: Expr

   code-conjure	Conjure.Engine

   map over the Int element type encoded as an Expr

   > mapE
   map :: (Int -> Int) -> [Int] -> [Int]
   

10. mapSubexprs :: (Expr -> Maybe Expr) -> Expr -> Expr

    code-conjure	Conjure.Engine

    O(n*m). Substitute subexpressions of an expression using the given function. Outer expressions have more precedence than inner expressions. (cf. //) With:

    > let xx = var "x" (undefined :: Int)
    > let yy = var "y" (undefined :: Int)
    > let zz = var "z" (undefined :: Int)
    > let plus = value "+" ((+) :: Int->Int->Int)
    > let times = value "*" ((*) :: Int->Int->Int)
    > let xx -+- yy = plus :$ xx :$ yy
    > let xx -*- yy = times :$ xx :$ yy
    

    > let pluswap (o :$ xx :$ yy) | o == plus = Just $ o :$ yy :$ xx
    |     pluswap _                           = Nothing
    

    Then:

    > mapSubexprs pluswap $ (xx -*- yy) -+- (yy -*- zz)
    y * z + x * y :: Int
    

    > mapSubexprs pluswap $ (xx -+- yy) -*- (yy -+- zz)
    (y + x) * (z + y) :: Int
    

    Substitutions do not stack, in other words a replaced expression or its subexpressions are not further replaced:

    > mapSubexprs pluswap $ (xx -+- yy) -+- (yy -+- zz)
    (y + z) + (x + y) :: Int
    

    Given that the argument function is O(m), this function is O(n*m).

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