谁能帮我将以下内容从happs“翻译”为happstack:
module Main where
import HAppS.Server.AlternativeHTTP
import HAppS.Server.HTTP.AltFileServe
import Control.Monad.State
import Numeric
import Contracts
instance FromData ExContr where
fromData = do c <- look "contract"
arg1 <- look "arg1"
arg2 <- look "arg2"
img <- look "image"
return $ ExContr (c, map fst $ readFloat arg1
++ readFloat arg2, read img)
main :: IO ()
main = do simpleHTTP [dir "contractEx"
[withData $ \(ExContr t) ->
[anyRequest $ liftIO $ liftM toResponse =<< renderEx (ExContr t)]
,anyRequest $ ok $ toResponse renderExDefault]
,fileServe ["Contracts.html"] "public" -- fileserving
]
Contracts.hs 包含:
newtype ExContr = ExContr (String, [Double], Bool) deriving (Read,Show,Eq)
renderEx :: ExContr -> IO Html
renderEx exSpec@(ExContr (contractId, args, lattice)) =
let pr = evalEx exSpec
expValChart = if contractId == "probs" then noHtml -- expected value is meaningless for the probabilities it relies on
else h3 << "Expected value" +++ image ! [src (chartUrl $ expectedValuePr pr)]
imageType = "png"
in if useLatticeImage exSpec
then do baseName <- mkUniqueName baseDotFilename
exitCode <- latticeImage pr (webPath ++ tmpImgPath ++ baseName) imageType
let pageContents =
case exitCode of
ExitSuccess -> renderExampleForm exSpec (image ! [src latticeUrl, border 1]) expValChart
where latticeUrl = "/" ++ tmpImgPath ++ baseName ++ "." ++ imageType
_ -> p << "renderEx: error generating lattice image"
return $ renderExamplePage pageContents
else return $ renderExamplePage $ renderExampleForm exSpec (prToTable pr) expValChart
renderExDefault = renderExamplePage $
renderExampleForm (ExContr ("zcb", [fromIntegral t1Horizon, 10], True))
noHtml noHtml
或者,我想了解如何安装与上述代码兼容的旧版 HappS。不用说我对 Haskell 很陌生。