Adding parser and gospers glider gun to be parsed by default

Author: jbrechtel

gospersGliderGun.txt

@@ -0,0 +1,11 @@
+............................................
+............................ ...............
+.......................... . ...............
+................  ......  ............  ....
+............... ... ....  ............  ....
+....  ........ ..... ...  ..................
+....  ........ ... .  .... . ...............
+.............. ..... ....... ...............
+............... ... ........................
+................  ..........................
+............................................

src/Life.hs

@@ -7,7 +7,7 @@ module Life
   , newWorldWithCells
   , size
   , evolve
-  , setCellAt
+  , updateCells
   , cellAt
   , cells
   , neighboringAddresses
@@ -27,7 +27,7 @@ instance Show World where
   show world = "World " ++ (show $ size world)
 
 newWorld :: Address -> World
-newWorld worldSize = newWorldWithCells worldSize (cycle [Dead, Alive])
+newWorld worldSize = newWorldWithCells worldSize (cycle [Dead])
 
 newWorldWithCells :: Address -> [Cell] -> World
 newWorldWithCells (width, height) cells = World $ listArray ((0,0), (width-1, height-1)) cells
@@ -40,8 +40,8 @@ evolve :: World -> World
 evolve world@(World ary) = World $ array (bounds ary) (map newCellAt $ indices ary)
   where newCellAt ix = (ix, fate (cellAt world ix) (map (cellAt world) (neighboringAddresses world ix)))
 
-setCellAt :: World -> Address -> Cell -> World
-setCellAt w _ _ = w
+updateCells:: World -> [(Address, Cell)] -> World
+updateCells (World ary) updates = World $ (ary // updates)
 
 cellAt :: World -> Address -> Cell
 cellAt (World ary) ix = ary ! ix

src/Pattern.hs

@@ -0,0 +1,26 @@
+module Pattern
+  ( Pattern
+  , loadPattern
+  , drawPatternAt
+  )
+  where
+
+import Data.List
+import Life
+
+data Pattern = Pattern ![(Address, Cell)] deriving (Show)
+
+loadPattern :: FilePath -> IO Pattern
+loadPattern filePath = do
+  fileContents <- readFile filePath
+  let parseChar '.' = Dead
+      parseChar ' ' = Alive
+      mapCell y x cell = (x+1, ((x,y), parseChar cell))
+      mapRow y row = (y+1, snd $ mapAccumL (mapCell y) 0 row)
+      patternCells = snd $ mapAccumL mapRow 0 (lines fileContents)
+  return $ Pattern (concat patternCells)
+
+drawPatternAt :: Address -> Pattern -> World -> World
+drawPatternAt (xOff, yOff) (Pattern updates) world = updateCells world (map offset updates)
+  where offset ((x, y), cell) = ((x + xOff, y + yOff), cell)
+

src/WebApp.hs

@@ -19,10 +19,13 @@ import qualified Text.Blaze.Html5 as H
 
 import           Life
 import           Timeline
+import           Pattern
 
 main :: IO ()
 main = do
-  timeline <- newTimeline (30, 30)
+  timeline <- newTimeline (50, 30)
+  pattern <- loadPattern "gospersGliderGun.txt"
+  interfere (drawPatternAt (0, 0) pattern) timeline
   quickServer $
         ifTop (writeBS "hello world") <|>
         route [ ("echo/:echoparam", echoHandler)