X-Git-Url: https://git.njae.me.uk/?a=blobdiff_plain;f=src%2Ftask1%2Ftask1.hs;h=b0e263031853ee045dcf3f6cdab8feceed1d4e8a;hb=HEAD;hp=200d538afd1fb1af0a401e81876003baf38fd865;hpb=2332d583ac8c5c998732c629cbb16f92b750ab1c;p=summerofcode2018soln.git

diff --git a/src/task1/task1.hs b/src/task1/task1.hs
index 200d538..b0e2630 100644
--- a/src/task1/task1.hs
+++ b/src/task1/task1.hs
@@ -1,18 +1,22 @@
 import Data.List (foldl')        -- import the strict fold
 
 -- number of steps
-type Step = Int
+type Distance = Int
+
+-- easting, northing
 type Position = (Int, Int)
 
+-- the directions. See below for functions for turning
 data Direction = North | East | South | West 
     deriving (Enum, Show, Bounded, Eq)
 
--- direction, easting, northing
+-- the currenct state of a Mowmaster
 data Mowmaster = Mowmaster { direction :: Direction 
                            , position :: Position
                            } deriving (Show, Eq)
 
-data Instruction =   Forward Step
+-- one instruction for the mowmaster
+data Instruction =   Forward Distance
                    | Clockwise 
                    | Anticlockwise
                    | Comment String
@@ -35,7 +39,6 @@ part2 instruction_text = finalDistance $ executeAll instructions
           executeAll = foldl' execute initialMowmaster
           
 
-
 -- Is this line a comment?
 isComment :: String -> Bool
 isComment ('#':_) = True
@@ -54,7 +57,7 @@ readInstruction i = readInstruction' (head i) (tail i)
           readInstruction'  _  t = Comment t
 
 
-initialMowmaster = Mowmaster North (0, 0)
+initialMowmaster = Mowmaster East (0, 0)
 
 
 -- Calculate manhattan distance from start to this state
@@ -70,14 +73,14 @@ execute m  Clockwise     = m {direction = turnCW (direction m)}
 execute m  Anticlockwise = m {direction = turnACW (direction m)}
 execute m (Comment _)    = m
 
+
 -- Move in the current direction
-forward :: Int -> Direction -> Position -> Position
+forward :: Distance -> Direction -> Position -> Position
 forward s North (e, n) = (e, n+s)
 forward s South (e, n) = (e, n-s)
 forward s West  (e, n) = (e-s, n)
 forward s East  (e, n) = (e+s, n)
 
-
 -- | a `succ` that wraps 
 turnCW :: (Bounded a, Enum a, Eq a) => a -> a 
 turnCW dir | dir == maxBound = minBound