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82 lines
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Haskell

module Main where
import Text.ParserCombinators.ReadP
import Control.Monad
import Control.Applicative
type HeaderLevel = Int
newtype URL = URL {getUrl :: String}
newtype ImgPath = ImgPath {getPath :: String}
data MdToken = Header HeaderLevel MdToken
| Para [MdToken]
| Linebreak
| HorizontalRule
| Blockquote MdToken
| UnordList [MdToken]
| OrdList [MdToken]
| Code String
| Codeblock String
| Link [MdToken] URL
| Image [MdToken] ImgPath
| Bold [MdToken]
| Italic [MdToken]
| Strikethrough [MdToken]
| Unit String
-- Deriving Show for MdToken
instance Show MdToken where
show (Header level token) = "<h" ++ show level ++ ">" ++ show token ++ "</h" ++ show level ++ ">"
show (Para tokens) = concat(map show tokens)
show Linebreak = "\n"
show HorizontalRule = "---------"
show (Blockquote token) = "BLOCK" ++ show token
show (UnordList tokens) = "UNORD" ++ concat(map show tokens)
show (OrdList tokens) = "ORD" ++ concat(map show tokens)
show (Code code) = concat(map show code)
show (Codeblock code) = concat(map show code)
show (Link txt url) = "<a href=" ++ (getUrl url) ++ ">" ++ concat(map show txt) ++ "</a>"
show (Image txt path) = "<img src=" ++ (getPath path) ++ ">" ++ concat(map show txt) ++ "</img>"
show (Bold tokens) = "<b>" ++ concat(map show tokens) ++ "</b>"
show (Italic tokens) = "<i>" ++ concat(map show tokens) ++ "</i>"
show (Strikethrough tokens) = "<s>" ++ concat (map show tokens) ++ "</s>"
show (Unit unit) = show unit
-- ---------------
-- Helpers
mustBeHash :: ReadP Char
mustBeHash = satisfy (\x -> x == '#')
-- ---------------
parseHeader :: ReadP MdToken
parseHeader = do
headers <- many1 mustBeHash
when ((length headers) > 6)
pfail
_ <- string " "
text <- munch1 (const True) -- Parse until EOL
return (Header (length headers) text)
parseBold :: ReadP MdToken
parseBold = do
_ <- string "__" <|> string "**"
text <- munch1 (\x -> x /= '_' && x /= '*') -- Parse until first asterisk/underscore
_ <- char '_' <|> char '*' -- Throw away the second asterisk/underscore
return (Bold text)
parseMain :: String -> []MdToken
parseMain
main :: IO ()
main = putStrLn "Hello, Haskell!"