Recursively collect eopkg revdeps

solo.hs

-- solo.hs // usage: solo <pkgs>

import Data.Function ((&))
import Data.List (isInfixOf, isSuffixOf, nub, sort)
import Data.List.Split (splitOn)
import System.Environment (getArgs)
import System.Process (readProcess)
import Text.Regex.PCRE ((=~))

eopkg_info :: [String] -> IO [String]
eopkg_info pkgs = do
  info <- readProcess "eopkg" ("info" : pkgs) []
  return $ splitOn "\n\n" info

revdeps_of :: [String] -> IO [String]
revdeps_of pkgs = do
  infos <- eopkg_info pkgs
  return $ infos
            & filter is_remote
            & map extract_revdeps
            & concat
            & filter (not.is_subpackage)
  where
    is_remote = isInfixOf "Package found"

    is_subpackage pkg = any (`isSuffixOf` pkg) ["dbginfo", "devel"]

    extract_revdeps :: String -> [String]
    extract_revdeps info = (info =~ "[^:]+\\z") & words

collect_revdeps :: [String] -> IO [String]
collect_revdeps start = do
  revdeps <- revdeps_of start
  if null revdeps then
    return start
  else do
    tree <- collect_revdeps revdeps
    return (start ++ revdeps ++ tree)

main = getArgs
        >>= collect_revdeps
        >>= putStr.unlines.sort.nub