我有以下代码,只是从这里复制粘贴和现代化(原始示例不再与最新版本的 Heist 编译)。
{-# LANGUAGE OverloadedStrings #-}
module Main where
import qualified Data.ByteString.Char8 as BS
import Data.Monoid
import Data.Maybe
import Data.List
import Control.Applicative
import Control.Lens
import Control.Monad.Trans
import Control.Monad.Trans.Either
import Heist
import Heist.Compiled
import Blaze.ByteString.Builder
conf :: HeistConfig IO
conf = set hcTemplateLocations [ loadTemplates "." ] $
set hcInterpretedSplices defaultInterpretedSplices $
emptyHeistConfig
runHeistConf :: Either [String] (HeistState IO) -> IO (HeistState IO)
runHeistConf (Right hs) = return hs
runHeistConf (Left msgs) = error . intercalate "\n" $ map ("[Heist error]: " ++) msgs
main :: IO ()
main = do
heist <- id <$> (runEitherT $ initHeist conf) >>= runHeistConf
output <- fst $ fromMaybe (error "xxx") $ renderTemplate heist "billy"
BS.putStrLn . toByteString $ output
以及以下模板:
<!-- billy.tpl -->
<bind tag="wanted">Playstation 4</bind>
<bind tag="got">Monopoly board game</bind>
<apply template="letter">
<bind tag="kiddo">Billy</bind>
I regret to inform you the "<wanted />" you have requested is currently
unavailable. I have substituted this with "<got />". I hope this does not
disappoint you.
</apply>
运行这个程序将整个模板(几乎)原样输出到控制台。不进行任何替代。现代 Hesit 版本可能需要一些函数调用。我试图在文档中追踪它,但没有运气。为什么它不起作用?
输出:
<!-- billy.tpl --><bind tag='wanted'>Playstation 4</bind> <bind tag='got'>Monopoly board game</bind>
<apply template='letter'>
<bind tag='kiddo'>Billy</bind>
I regret to inform you the "<wanted></wanted>" you have requested is currently
unavailable. I have substituted this with "<got></got>". I hope this does not
disappoint you.
</apply>