content: {-
      Copyright 2016 Markus Ongyerth
  
      This file is part of Monky.
  
      Monky is free software: you can redistribute it and/or modify
      it under the terms of the GNU Lesser General Public License as published by
      the Free Software Foundation, either version 3 of the License, or
      (at your option) any later version.
  
      Monky is distributed in the hope that it will be useful,
      but WITHOUT ANY WARRANTY; without even the implied warranty of
      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      GNU Lesser General Public License for more details.
  
      You should have received a copy of the GNU Lesser General Public License
      along with Monky.  If not, see <http://www.gnu.org/licenses/>.
  -}
  {-# LANGUAGE CPP #-}
  {-|
  Module      : Monky.Output.Modify
  Description : Monky module that modifies other outputs behaviour
  Maintainer  : ongy
  Stability   : testing
  Portability : Linux
  
  -}
  module Monky.Outputs.Modify
    ( ModifyOutput
    , getModifyOutput
    )
  where
  
  #if MIN_VERSION_base(4,8,0)
  #else
  import Control.Applicative ((<$>))
  #endif
  
  import Monky.Modules
  
  -- |Handle for modifying a line before it's passed to the output
  data ModifyOutput a = MH ([[MonkyOut]] -> [[MonkyOut]]) a
  
  -- |Get a handle to purely modify a line
  getModifyOutput :: ([[MonkyOut]] -> [[MonkyOut]]) -> IO a -> IO (ModifyOutput a)
  getModifyOutput = fmap . MH
  
  instance MonkyOutput a => MonkyOutput (ModifyOutput a) where
      doLine (MH f x) line = doLine x $ f line
  