shell for script to turn pandoc math to svg

gistfile1.hs

-- math2svg.hs
-- compile with:
-- ghc --make math2svg.hs
-- run using:
-- pandoc -t json -s | ./math2svg | pandoc -f json

mport Text.Pandoc
import Text.JSON.Generic
import System.Cmd
import System.Posix.Directory
import System.IO
import System.IO.Temp
import System.Process

main = getContents >>= transform . decodeJSON >>= putStrLn . encodeJSON

transform :: Pandoc -> IO Pandoc
transform = bottomUpM mathToSvg

mathToSvg :: Inline -> IO Inline
mathToSvg (Math mathType x) = do
  let delim = case mathType of 
                   InlineMath -> "$"
                   DisplayMath -> "$$"
  withSystemTempDirectory "pandoc." $ \tmpDir ->
    do 
       changeWorkingDirectory tmpDir
       phandle <- runProcess "tex" 
                             [("\\nopagenumbers " ++ delim ++ filter (/='\n') x ++ delim ++ " \\bye")]
                             Nothing Nothing Nothing (Just stderr) Nothing
       waitForProcess phandle
       shandle <- runProcess "dvisvgm"
                             ["-e", "-n", "texput.dvi"]
                             Nothing Nothing Nothing Nothing Nothing
       waitForProcess shandle
       svg <- readFile "texput.svg"
       return (RawInline "html" svg)
mathToSvg x = return x