modify -package:data-accessor

Monadic state transformer. Maps an old state to a new state inside a state monad. The old state is thrown away.

Main> :t modify ((+1) :: Int -> Int)
modify (...) :: (MonadState Int a) => a ()

This says that modify (+1) acts over any Monad that is a member of the MonadState class, with an Int state.

modify f is an action that updates the state to the result of applying f to the current state.

• modify f = get >>= (put .
  f)

modify f is an action that updates the state to the result of applying f to the current state.

• modify f = get >>= (put .
  f)

modify f is an action that updates the state to the result of applying f to the current state.

• modify f = get >>= (put .
  f)

Modify the state.

Apply a destructive operation to a vector. The operation will be performed in place if it is safe to do so and will modify a copy of the vector otherwise.

modify (\v -> write v 0 'x') (replicate 3 'a') = <'x','a','a'>

Apply a destructive operation to a vector. The operation will be performed in place if it is safe to do so and will modify a copy of the vector otherwise.

modify (\v -> write v 0 'x') (replicate 3 'a') = <'x','a','a'>

Apply a destructive operation to a vector. The operation will be performed in place if it is safe to do so and will modify a copy of the vector otherwise.

modify (\v -> write v 0 'x') (replicate 3 'a') = <'x','a','a'>

Apply a destructive operation to a vector. The operation will be performed in place if it is safe to do so and will modify a copy of the vector otherwise.

modify (\v -> write v 0 'x') (replicate 3 'a') = <'x','a','a'>

Monadic state transformer. Maps an old state to a new state inside a state monad. The old state is thrown away.

Main> :t modify ((+1) :: Int -> Int)
modify (...) :: (MonadState Int a) => a ()

This says that modify (+1) acts over any Monad that is a member of the MonadState class, with an Int state.

Set the label to the result of applying the given function to the value.

Modify the contents of an RWVar and return an additional value. Like modify_, but allows a value to be returned (β) in addition to the modified value of the RWVar.

VS.unpack $ runSTVector (do arr <- new 10 'a'; Monad.mapM_ (\n -> modify arr (mod n 8) succ) [0..10]; return arr)

Modify the elements of a mutable array in-place.

Apply the function to the current state.

modify f ≡ state (\s -> ((), f s))

Apply the function to the current state.

modify f ≡ state (\s -> ((), f s))

Note: this function gets an exclusive access to the state for its duration.

Replace the state value with the result of applying a function to the current state value. This is strict in the new state.

modify f = get >>= (put . f $!)

O(1) Modify the element at a given type-safe position using Finite.

O(1) Modify the element at a given type-safe position using Finite.

O(1) Modify the element at a given type-safe position using Finite.

O(1) Modify the element at a given type-safe position using Finite.

O(1) Modify the element at a given type-safe position using Finite.

O(1) - Modify an element in the cell of a mutable array with a supplied action. Returns the previous value, if index was not out of bounds.