Point.hs

   1 {-# LANGUAGE TypeSynonymInstances #-}
   2
   3 module Point
   4 where
   5
   6 type Point = (Double, Double, Double)
   7
   8 x_coord :: Point -> Double
   9 x_coord (x, _, _) = x
  10
  11 y_coord :: Point -> Double
  12 y_coord (_, y, _) = y
  13
  14 z_coord :: Point -> Double
  15 z_coord (_, _, z) = z
  16
  17 instance Num Point where
  18     p1 + p2 = (x1+x2, y1+y2, z1+z2)
  19         where
  20           x1 = x_coord p1
  21           x2 = x_coord p2
  22           y1 = y_coord p1
  23           y2 = y_coord p2
  24           z1 = z_coord p1
  25           z2 = z_coord p2
  26
  27     p1 - p2 = (x1-x2, y1-y2, z1-z2)
  28         where
  29           x1 = x_coord p1
  30           x2 = x_coord p2
  31           y1 = y_coord p1
  32           y2 = y_coord p2
  33           z1 = z_coord p1
  34           z2 = z_coord p2
  35
  36     p1 * p2 = (x1*x2, y1*y2, z1*z2)
  37         where
  38           x1 = x_coord p1
  39           x2 = x_coord p2
  40           y1 = y_coord p1
  41           y2 = y_coord p2
  42           z1 = z_coord p1
  43           z2 = z_coord p2
  44
  45     abs (x, y, z) = (abs x, abs y, abs z)
  46     signum (x, y, z) = (signum x, signum y, signum z)
  47     fromInteger n = (fromInteger n, fromInteger n, fromInteger n)
  48
  49
  50 scale :: Point -> Double -> Point
  51 scale (x, y, z) d = (x*d, y*d, z*d)