From: Michael Orlitzky <michael@orlitzky.com>
Date: Mon, 2 May 2011 20:37:13 +0000 (-0400)
Subject: Add distance and is_close functions to the Point module.
X-Git-Tag: 0.0.1~348
X-Git-Url: https://gitweb.michael.orlitzky.com/?a=commitdiff_plain;h=8b9be083a95b604a296a31dcc9a275391ebb2591;p=spline3.git

Add distance and is_close functions to the Point module.
---

diff --git a/src/Point.hs b/src/Point.hs
index d0859bf..5d7954c 100644
--- a/src/Point.hs
+++ b/src/Point.hs
@@ -3,6 +3,9 @@
 module Point
 where
 
+import Comparisons
+
+
 type Point = (Double, Double, Double)
 
 x_coord :: Point -> Double
@@ -49,3 +52,19 @@ instance Num Point where
 
 scale :: Point -> Double -> Point
 scale (x, y, z) d = (x*d, y*d, z*d)
+
+
+distance :: Point -> Point -> Double
+distance p1 p2 =
+    sqrt $ (x2 - x1)^(2::Int) + (y2 - y1)^(2::Int) + (z2 - z1)^(2::Int)
+    where
+      x1 = x_coord p1
+      x2 = x_coord p2
+      y1 = y_coord p1
+      y2 = y_coord p2
+      z1 = z_coord p1
+      z2 = z_coord p2
+
+
+is_close :: Point -> Point -> Bool
+is_close p1 p2 = (distance p1 p2) ~= 0