Extend hoogle database

exthoo.hs

#!/usr/bin/env stack
-- stack --resolver global runghc --package turtle

{-# LANGUAGE OverloadedStrings #-}
import Turtle
import qualified Data.Text as T

parser :: Parser Text
parser = argText "pkg"  "Package name"

main :: IO ()
main = sh $ do
    pkg <- options "Extend hoogle database" parser
    h <- home
    p <- pathToText <$> find (has "hoogle" <> suffix "databases") (h </> ".stack")
    cd . fromText . T.init $ p
    result <- shell' $ format ("wget https://hackage.haskell.org/package/"
                               %s%"/docs/"%s%".txt") pkg pkg
    case result of
        ExitFailure _ -> error "package not found"
        _ -> return ()

    shell' $ format ("hoogle convert "%s%".txt") pkg
    shell' $ format ("hoogle combine default.hoo "%s%".hoo -o new.hoo") pkg
    mv "new.hoo" "default.hoo"

  where shell' = flip shell empty
        pathToText = either (error "hoogle databases not found") id . toText