看完一段视频后布雷特·维克多的演讲 http://vimeo.com/36579366，我受到启发，编写了一个快速破解程序，该程序与他在演讲中演示的开发环境有些相似。
基本上，其想法是，让应用程序在一个窗口中运行，每当在源文件中保存更改时，程序就会更改。
这对于小的更改非常有效，除了我无法在不关闭应用程序并重新编译的情况下更改代码中的状态类型。
如何解决表达问题并使我的状态的数据类型能够改变
不会导致重新编译？
附：
这是代码。
我本来不想发帖，因为它真的很乱，而且很快就被拼凑在一起了，但人们想要它，这样他们就能得到它。
首先是显示器和空闲模块（这是一个快速破解，所以我不知道如何将它们作为真正的模块来实现）。
Idle.hs
\state -> do
counter <- readIORef state
writeIORef state ((counter + 1)`mod`3)
postRedisplay Nothing
显示.hs
\state -> let
cube w = do
renderPrimitive Quads $ do
vertex $ Vertex3 w w w
vertex $ Vertex3 w w (-w)
vertex $ Vertex3 w (-w) (-w)
vertex $ Vertex3 w (-w) w
vertex $ Vertex3 w w w
vertex $ Vertex3 w w (-w)
vertex $ Vertex3 (-w) w (-w)
vertex $ Vertex3 (-w) w w
vertex $ Vertex3 w w w
vertex $ Vertex3 w (-w) w
vertex $ Vertex3 (-w) (-w) w
vertex $ Vertex3 (-w) w w
vertex $ Vertex3 (-w) w w
vertex $ Vertex3 (-w) w (-w)
vertex $ Vertex3 (-w) (-w) (-w)
vertex $ Vertex3 (-w) (-w) w
vertex $ Vertex3 w (-w) w
vertex $ Vertex3 w (-w) (-w)
vertex $ Vertex3 (-w) (-w) (-w)
vertex $ Vertex3 (-w) (-w) w
vertex $ Vertex3 w w (-w)
vertex $ Vertex3 w (-w) (-w)
vertex $ Vertex3 (-w) (-w) (-w)
vertex $ Vertex3 (-w) w (-w)
points :: Integer -> [(GLfloat,GLfloat,GLfloat)]
points n' = let n = fromIntegral n' in map (\k -> let t = 2*pi*k/n in (sin(t),cos(t),0.0)) [1..n]
in do
clear [ ColorBuffer ]
counter <- readIORef state
mapM_ (\(x,y,z) -> preservingMatrix $ do
color $ Color3 ((x+1.0)/2.0) ((y+1.0)/2.0) ((z+1.0)/2.0)
translate $ Vector3 x y z
cube (0.3::GLfloat)
) $ points (9 + counter)
flush
主要模块
module Main where
import Control.Monad
import Data.Typeable as Typeable
import System.IO
import Data.IORef
import Graphics.Rendering.OpenGL
import Graphics.UI.GLUT
import Language.Haskell.Interpreter
main :: IO ()
main = do
(_, _) <- getArgsAndInitialize
createWindow "Hello World"
action <- newIORef $ do
clear [ ColorBuffer ]
flush
let imports = ["Prelude", "Data.IORef", "Graphics.Rendering.OpenGL", "Graphics.UI.GLUT"]
let modules = ["State"]
runFile (undefined :: IORef Integer -> IO ()) "Display.hs" imports $ \displayCode ->
runFile (undefined :: IORef Integer -> IO ()) "Idle.hs" imports $ \idleCode -> do
state <- newIORef 12
displayCallback $= display displayCode state
idleCallback $= Just (idle displayCode idleCode state)
mainLoop
display displayCode state = do
f <- execute displayCode
f state
idle displayCode idleCode state = do
update displayCode
update idleCode
f <- execute idleCode
f state
instance Eq GhcError where
GhcError s == GhcError t = s == t
instance Eq InterpreterError where
UnknownError s == UnknownError t = s == t
WontCompile s == WontCompile t = s == t
NotAllowed s == NotAllowed t = s == t
GhcException s == GhcException t = s == t
data V a = V {
update :: IO (),
execute :: IO a
}
runFile :: Typeable a => a -> String -> [String] -> (V a -> IO ()) -> IO ()
runFile theType file imports f = do
currentError <- newIORef Nothing
currentAction <- newIORef Nothing
let v = V {
update = do
fileContents <- readFile file
result <- runInterpreter $ do
setImports imports
interpret fileContents theType
oldError <- readIORef currentError
case result of
Right newAction -> do
when (oldError /= Nothing) $ do
writeIORef currentError Nothing
putStrLn (file ++ " Ok!")
writeIORef currentAction (Just newAction)
Left newError -> do
when ((Just newError) /= oldError) $ do
writeIORef currentError (Just newError)
print newError
, execute = do
action <- readIORef currentAction
case action of
Nothing -> do
err <- readIORef currentError
return (error (show err))
Just act -> return act
}
update v
f v
