26-151904.hs

module Shapes
       ( Point (..),
         Shape (..),
         area,
         nudge,
         baseCircle,
         baseRect ) where

-- data Bool = False | True

-- data Shape = Circle Float Float Float |
--              Rectangle Float Float Float Float
--            deriving (Show)

data Point = Point Float Float deriving (Show)

data Shape = Circle Point Float | Rectangle Point Point deriving (Show)

area :: Shape -> Float
area (Circle _ r) = pi * r ^ 2
area (Rectangle (Point x1 y1) (Point x2 y2)) = (abs $ x2 - x1) * (abs $ y2 - y1)

nudge :: Shape -> Float -> Float -> Shape
nudge (Circle (Point x y) r) a b = Circle (Point (x + a) (y + b)) r
nudge (Rectangle (Point x1 y1) (Point x2 y2)) a b =
  Rectangle (Point (x1 + a) (y1 + b)) (Point (x2 + a) (y2 + b))

baseCircle :: Float -> Shape
baseCircle r = Circle (Point 0 0) r

baseRect :: Float -> Float -> Shape
baseRect a b = Rectangle (Point 0 0) (Point a b)