module Data.Accessor.Example where

import Data.Accessor.Basic ((.>), ($%), (^.), (^:), (^=), )
import Data.Accessor.Tuple (first, second, )

import qualified Data.Accessor.Basic as Accessor
import qualified Data.Accessor.BinaryRead as Read
import qualified Data.Accessor.Show as Show

import Data.Accessor.MonadState ((%=), (%:), )
import qualified Data.Accessor.MonadState as AState
import Control.Monad.State (State)
import Data.Char (ord, )

import Prelude hiding (init)


{- * Example accesses -}

{- | Example of using 'set', 'get', 'modify'. -}
plain :: Int
plain =
   Accessor.get second $
   Accessor.modify second succ $
   Accessor.set first 'a' $
   ('b',7)

state :: State (Char,Int) Int
state =
   do AState.set first 'a'
      AState.modify second succ
      AState.get second

stateInfix :: State ((Char, Int), String) Int
stateInfix =
   do str <- AState.get second
      first.>first %= 'a'
      first.>second %: succ
      first.>first %= 'b'
      second %= '!' : str
      AState.get (first.>second)

init :: (Char,Int)
init =
   Accessor.compose
      [Accessor.set first 'b',
       Accessor.modify first succ,
       Accessor.set second 7]
      (undefined,undefined)
--   setMany [first 'b', second 7] (undefined,undefined)

initInfix :: (Char,Int)
initInfix =
   (undefined,undefined)
   $% first ^= 'b'
   $% first ^: succ
   $% second ^= 7

read :: Maybe ((Char,Int), Read.Stream)
read =
   Read.runParser
      (Read.record [Read.field first, Read.field second])
      ((undefined,undefined),
       fromIntegral (ord 'c') : 59 : 154 : 202 : 0 : [])

infix0 :: Int
infix0 =
   (('b',7),"hallo")^.first^.second

infix1 :: ((Char, Int), String)
infix1 =
   (('b',7),"hallo")$%first^:second^:(1+)

infix2 :: ((Char, Int), String)
infix2 =
   (('b',7),"hallo")$%first^:second^=10

infix3 :: Int
infix3 =
   (('b',7),"hallo")^.(first.>second)

infix4 :: ((Char, Int), String)
infix4 =
   (('b',7),"hallo")$%(first.>second)^:(1+)


showsPair :: Int -> (Char, Int) -> ShowS
showsPair =
   Show.showsPrec
      [Show.field "first"  first,
       Show.field "second" second]
      "init" init

show0 :: String
show0 = showsPair 11 init ""

show1 :: String
show1 = showsPair 5 ('d',8) ""