modify

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.

Transform the value of a field by a function.

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))

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.