X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FCardinal.hs;h=0a1b139ca8b87546b0bd3f9d19ea36a58fe413e5;hb=408f4da9058366cd8047592aa96f97bcc348d329;hp=f62896f9f3615bef495c99e045857c4748a491ac;hpb=6fb9ab6b6068870323e996da931fc04c7710e3e4;p=spline3.git

diff --git a/src/Cardinal.hs b/src/Cardinal.hs
index f62896f..0a1b139 100644
--- a/src/Cardinal.hs
+++ b/src/Cardinal.hs
@@ -1,6 +1,8 @@
 module Cardinal
 where
 
+import Prelude hiding (LT)
+
 data Cardinal = F
               | B
               | L
@@ -48,3 +50,83 @@ instance Fractional Cardinal where
     x / y   = Quotient x y
     recip x = Quotient (Scalar 1) x
     fromRational x = Scalar (fromRational x)
+
+-- | Rotate a cardinal direction counter-clockwise about the x-axis.
+ccwx :: Cardinal -> Cardinal
+ccwx F = F
+ccwx B = B
+ccwx L = T
+ccwx R = D
+ccwx D = L
+ccwx T = R
+ccwx FL = FT
+ccwx FR = FD
+ccwx FD = FL
+ccwx FT = FR
+ccwx BL = BT
+ccwx BR = BD
+ccwx BD = BL
+ccwx BT = BR
+ccwx LD = LT
+ccwx LT = RT
+ccwx RD = LD
+ccwx RT = RD
+ccwx FLD = FLT
+ccwx FLT = FRT
+ccwx FRD = FLD
+ccwx FRT = FRD
+ccwx BLD = BLT
+ccwx BLT = BRT
+ccwx BRD = BLD
+ccwx BRT = BRD
+ccwx I = I
+ccwx (Scalar s) = (Scalar s)
+ccwx (Sum c0 c1) = Sum (ccwx c0) (ccwx c1)
+ccwx (Difference c0 c1) = Difference (ccwx c0) (ccwx c1)
+ccwx (Product c0 c1) = Product (ccwx c0) (ccwx c1)
+ccwx (Quotient c0 c1) = Quotient (ccwx c0) (ccwx c1)
+
+-- | Rotate a cardinal direction clockwise about the x-axis.
+cwx :: Cardinal -> Cardinal
+cwx = ccwx . ccwx . ccwx
+
+
+-- | Rotate a cardinal direction counter-clockwise about the y-axis.
+--   TODO: Fix these; they still use the x-axis values.
+ccwy :: Cardinal -> Cardinal
+ccwy F = F
+ccwy B = B
+ccwy L = T
+ccwy R = D
+ccwy D = L
+ccwy T = R
+ccwy FL = FT
+ccwy FR = FD
+ccwy FD = FL
+ccwy FT = FR
+ccwy BL = BT
+ccwy BR = BD
+ccwy BD = BL
+ccwy BT = BR
+ccwy LD = LT
+ccwy LT = RT
+ccwy RD = LD
+ccwy RT = RD
+ccwy FLD = FLT
+ccwy FLT = FRT
+ccwy FRD = FLD
+ccwy FRT = FRD
+ccwy BLD = BLT
+ccwy BLT = BRT
+ccwy BRD = BLD
+ccwy BRT = BRD
+ccwy I = I
+ccwy (Scalar s) = (Scalar s)
+ccwy (Sum c0 c1) = Sum (ccwy c0) (ccwy c1)
+ccwy (Difference c0 c1) = Difference (ccwy c0) (ccwy c1)
+ccwy (Product c0 c1) = Product (ccwy c0) (ccwy c1)
+ccwy (Quotient c0 c1) = Quotient (ccwy c0) (ccwy c1)
+
+-- | Rotate a cardinal direction clockwise about the x-axis.
+cwy :: Cardinal -> Cardinal
+cwy = ccwy . ccwy . ccwy