module Week06 where

import Debug.Trace(trace)

type Point = (Xordinate,Yordinate)
type Xordinate = Float
type Yordinate = Float

distance :: Point -> Point -> Float

distance (x1,y1) (x2,y2)
   = sqrt (xDifference^2 + yDifference^2)
   where
      xDifference = x1 - x2
      yDifference = y1 - y2


-- type Color = (Int,Int,Int)

data Color = Red | Green | Black | Yellow | White | Orange | Puce
   deriving (Eq, Show, Ord, Enum)

{-
data Bool = True | False 
   deriving (Show,Eq,Enum,Ord)
-}


myLength' :: [a] -> Int
myLength' [] = 0
myLength' (_:rest) = 1 + (myLength' rest)

myLength :: (Eq a) => [a] -> Int
myLength list
  | list == [] = 0
  | otherwise  = 1 + (myLength rest)
  where
    rest = tail list


type Name = String

fave :: Name -> Color
fave "julia" = Red
fave "david" = Puce
fave "angel" = Black

data Shape = Square Float | Circle Float | 
             Triangle Float Float Float
    deriving (Eq, Show)

perimeter :: Shape -> Float
perimeter (Square side)      = 4 * side
perimeter (Triangle a b c)   = 
   Debug.Trace.trace "its a triangle!" (a + b + c)
perimeter (Circle radius)    = 2 * pi * radius