modify package:transformers

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)

A variant of modify in which the computation is strict in the new state.

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

A variant of modify in which the new state is generated by a monadic action.

A variant of modify in which the computation is strict in the new state.

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

Note that this is only strict in the top level of the state. Lazy components of the state will not be evaluated unless f evaluates them.