这只是丹尼尔之后的另一种想法。它看起来像你的Grids
只是Colors
它可能不会为一个小的“网格”做很多事情,但是为Color
制作一个Unbox
实例相对比较容易。然后一个网格将包含一个未装箱的数组。在Grid.hs
中,您将导入Data.Vector.Unboxed
而不是Data.Vector
。这通常是多更好的原因有很多,但会要求你对许多定义加上Unbox a =>
约束。如果您想将网格映射为除Color
之外的其他类型的网格,则这可能会产生后果,除非它具有Unbox
实例。
下面我刚刚从vector-th-unbox
(我刚刚了解到该软件包,并且正在考虑再次测试它)和两个必需的定义中添加TH咒语。在Data.Vector.Unboxed.Base
的Bool实例中手动编写它并不困难。
{-#LANGUAGE TemplateHaskell, TypeFamilies, MultiParamTypeClasses#-}
module Color where
import Display
import Data.Vector.Unboxed.Deriving
import qualified Data.Vector.Unboxed as V
import qualified Data.Vector.Generic as G
import qualified Data.Vector.Generic.Mutable as M
import Data.Word (Word8)
data Color = Yellow | Red | Green | Blue | Empty
deriving (Show, Eq, Ord, Enum, Bounded)
fromColor :: Color -> Word8
{-# INLINE fromColor #-}
fromColor = fromIntegral . fromEnum
toColor :: Word8 -> Color
{-# INLINE toColor #-}
toColor x | x < 5 = toEnum (fromIntegral x)
toColor _ = Empty
derivingUnbox "Color"
[t| Color -> Word8 |]
[| fromColor |]
[| toColor |]
-- test
colorCycle :: Int -> V.Vector Color
colorCycle n = V.unfoldr colorop 0 where
colorop m | m < n = Just (toColor (fromIntegral (m `mod` 5)),m+1)
colorop _ = Nothing
-- *Colour> colorCycle 12
-- fromList [Yellow,Red,Green,Blue,Empty,Yellow,
-- Red,Green,Blue,Empty,Yellow,Red]
colorBlack = "\ESC[0;30m"
colorRed = "\ESC[0;31m"
colorGreen = "\ESC[0;32m"
colorYellow = "\ESC[0;33m"
colorBlue = "\ESC[0;34m"
instance Display Color where
display Red = colorRed ++ "R" ++ colorBlack
display Green = colorGreen ++ "G" ++ colorBlack
display Yellow = colorYellow ++ "Y" ++ colorBlack
display Blue = colorBlue ++ "B" ++ colorBlack
display Empty = "."
编辑:在vector-th-unbox
版本0.1
以下模板前使用:
derivingUnbox "Color"
[d| instance Unbox' (Color) Word8 |]
[| fromColor |]
[| toColor |]
谢谢!这在另一个地方解决了这个问题。 – Drew