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Convert Bird-style .lhs to Markdown.
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#!/usr/bin/env stack | |
-- stack runghc --package text --package turtle | |
{-# LANGUAGE OverloadedStrings #-} | |
{- | |
lxx2md.hs (-l|--lang LANG) | |
A filter that converts Bird-style lhs in Markdown ``` blocks. | |
Combines consecutive Bird-tracked lines into single blocks. | |
KNOWN ISSUES | |
- Does not reject program lines next to text lines. | |
- Assumes that newlines are \n. | |
COPYING | |
Do whatever you want - but it'd be nice to know how things | |
get improved. | |
-} | |
import Turtle | |
import qualified Data.Text.Lazy as L | |
import qualified Data.Text.Lazy.IO as L | |
data Block = Text L.Text | Code L.Text | |
deriving Show | |
main :: IO () | |
main = do | |
lang <- (fmap L.fromStrict) (options "lxx2md" opts) | |
lines <- (fmap L.lines) L.getContents | |
putLines (map (render lang) (coalesce $ parse lines)) | |
return () | |
where opts = optText "lang" 'l' "The language string Markdown code blocks are given." | |
parse :: [L.Text] -> [Block] | |
parse [] = [] | |
parse (l:ls) = case L.stripPrefix ">" l of | |
Nothing -> Text l : parse ls | |
Just l' -> Code l' : parse ls | |
coalesce :: [Block] -> [Block] | |
coalesce [] = [] | |
coalesce [a] = [a] | |
coalesce (Text a:Text b:cs) = | |
coalesce $ Text (a +++ "\n" +++ b) : coalesce cs | |
coalesce (Code a:Code b:cs) = | |
coalesce $ Code (a +++ "\n" +++ b) : coalesce cs | |
coalesce (a:b:cs) = a : b : coalesce cs | |
render :: L.Text -> Block -> L.Text | |
render ____ (Text text) = text | |
render lang (Code text) = "```" +++ lang +++ "\n" +++ text +++ "\n```" | |
putLines :: [L.Text] -> IO [()] | |
putLines = mapM L.putStrLn | |
(+++) = L.append |
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