import Text.Printf

edge = 28.223 :: Double
spacing = 32 :: Double
gap = spacing - edge
across = [("light", "left"), ("dark", "right"), ("dark", "left"), ("light", "right")]
down = ["king", "queen", "bishop", "knight", "rook", "pawn"]

useElement :: Double -> Double -> String -> String -> String -> String
useElement x y side kind place = printf format name x y edge edge x y name
   where
      format =
         "<view id=\"%s\" width=\"80pt\" height=\"80pt\" viewBox=\"%.3f %.3f %.3f %.3f\"/>\n" ++
         "<use transform=\"translate(%.3f %.3f)\" xlink:href=\"#sym_%s\"/>"
      name = side ++ "_" ++ kind ++ "_" ++ place

main = do
   putStr $ unlines $ concat $
      flip map (zip [5*spacing,4*spacing..] down) $ \(y, kind) ->
         flip map (zip [0,spacing..] across) $ \(x, (side, place)) ->
            useElement x y side kind place
   putStr "<path stroke-width=\"0.25\" stroke=\"#000\" d=\""
   putStr $ flip concatMap [0..6] $ \row ->
      printf "M%0.3f %0.3fH%0.3f" (0 - gap/2) (row*spacing-(gap/2)) (4*spacing - gap/2)
   putStr $ flip concatMap [0..4] $ \col ->
      printf "M%0.3f %0.3fV%0.3f" (col*spacing-(gap/2)) (0 - gap/2) (6*spacing - gap/2)
   putStrLn "\"/>"
   printf "viewBox=\"%.3f %0.3f %.3f %.3f\"\n"
      (0-spacing) (0-gap) (6*spacing + 2*gap) (6*spacing + 2*gap)