-------------------------------------------------------------------------
--  
--         Types.hs                         
--  
--         The types used in the Huffman coding example.            
--                                  
--         (c) Addison-Wesley, 1996-2011.                   
--  
-------------------------------------------------------------------------

-- The interface to the module Types is written out     
-- explicitly here, after the module name.                      

module Types ( Tree(Leaf,Node), Bit(L,R),  
               HCode , Table  ) where

-- Trees to represent the relative frequencies of characters    
-- and therefore the Huffman codes.                     

data Tree = Leaf Char Int | Node Int Tree Tree

-- The types of bits, Huffman codes and tables of Huffman codes.    

data Bit = L | R deriving (Bit -> Bit -> Bool
(Bit -> Bit -> Bool) -> (Bit -> Bit -> Bool) -> Eq Bit
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
$c== :: Bit -> Bit -> Bool
== :: Bit -> Bit -> Bool
$c/= :: Bit -> Bit -> Bool
/= :: Bit -> Bit -> Bool
Eq,Int -> Bit -> ShowS
[Bit] -> ShowS
Bit -> String
(Int -> Bit -> ShowS)
-> (Bit -> String) -> ([Bit] -> ShowS) -> Show Bit
forall a.
(Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
$cshowsPrec :: Int -> Bit -> ShowS
showsPrec :: Int -> Bit -> ShowS
$cshow :: Bit -> String
show :: Bit -> String
$cshowList :: [Bit] -> ShowS
showList :: [Bit] -> ShowS
Show)

type HCode = [Bit]

type Table = [ (Char,HCode) ]