nixpkgsDrvs.hs

{-# LANGUAGE FlexibleContexts  #-}
{-# LANGUAGE NamedFieldPuns    #-}
{-# LANGUAGE OverloadedStrings #-}
module Main where

import           Nix

import           Control.Monad
import           Control.Monad.Trans
import qualified Data.HashMap.Strict as H
import           Data.Maybe
import           Data.Text           (Text)
import qualified Data.Text           as Text
import qualified Data.Text.IO        as TextIO
import           Data.Time
import           Nix.Utils

getDrvs :: MonadThunk (NValue m) (NThunk m) m => AttrSet (NThunk m) -> m [(Text, AttrSet (NThunk m))]
getDrvs set = do
  attrs <- mapM (\(n, t) -> force t $ \v -> case _baseValue v of
                    NVSetF x _ -> return (Just (n, x))
                    _          -> return Nothing
                ) (H.toList set)
  filterM (\(n, v) -> isDerivation v) (catMaybes attrs)

nixpkgs :: (MonadIO m, MonadNix e m, Has e Options) => m (NValue m)
nixpkgs = do
  let path = "/home/infinisil/src/nixpkgs/default.nix"
  r <- parseNixFileLoc path
  case r of
    Failure doc  -> fail (show doc)
    Success expr -> nixEvalExprLoc (Just path) expr

program :: (MonadIO m, MonadNix e m, Has e Options) => m ()
program = do
  n <- nixpkgs
  case _baseValue n of
    NVSetF set _ -> do
      drvs <- getDrvs set
      liftIO . print $ "The first 10 derivations are:"
      liftIO . print . map fst . take 10 $ drvs
      return ()
    _ -> fail "Nixpkgs is no attrset???"

main :: IO ()
main = do
  time <- liftIO getCurrentTime
  let opts = defaultOptions time
  runLazyM opts program