{-# LANGUAGE NoImplicitPrelude #-}

{-# LANGUAGE RecordWildCards, DeriveDataTypeable, OverloadedStrings #-}

-- | Nix configuration

module Stack.Config.Nix

(nixOptsFromMonoid

,nixCompiler

,StackNixException(..)

) where

import Stack.Prelude

import qualified Data.Text as T

import Distribution.System (OS (..))

import Stack.Types.Version

import Stack.Types.Nix

import Stack.Types.Compiler

-- | Interprets NixOptsMonoid options.

nixOptsFromMonoid

:: MonadUnliftIO m

=> NixOptsMonoid

-> OS

-> m NixOpts

nixOptsFromMonoid NixOptsMonoid{..} os = do

let nixEnable = fromFirst (getAny nixMonoidDefaultEnable) nixMonoidEnable

defaultPure = case os of

OSX -> False

_ -> True

nixPureShell = fromFirst defaultPure nixMonoidPureShell

nixPackages = fromFirst [] nixMonoidPackages

nixInitFile = getFirst nixMonoidInitFile

nixShellOptions = fromFirst [] nixMonoidShellOptions

++ prefixAll (T.pack "-I") (fromFirst [] nixMonoidPath)

nixAddGCRoots = fromFirst False nixMonoidAddGCRoots

when (not (null nixPackages) && isJust nixInitFile) $

throwIO NixCannotUseShellFileAndPackagesException

return NixOpts{..}

where prefixAll p (x:xs) = p : x : prefixAll p xs

prefixAll _ _ = []

nixCompiler :: CompilerVersion a -> Either StringException T.Text

nixCompiler compilerVersion =

let -- These are the latest minor versions for each respective major version available in nixpkgs

fixMinor "8.2" = "8.2.1"

fixMinor "8.0" = "8.0.2"

fixMinor "7.10" = "7.10.3"

fixMinor "7.8" = "7.8.4"

fixMinor "7.6" = "7.6.3"

fixMinor "7.4" = "7.4.2"

fixMinor "7.2" = "7.2.2"

fixMinor "6.12" = "6.12.3"

fixMinor "6.10" = "6.10.4"

fixMinor v = v

nixCompilerFromVersion v = T.append (T.pack "haskell.compiler.ghc")

(T.filter (/= '.')

(fixMinor (versionText v)))

in case compilerVersion of

GhcVersion v -> Right $ nixCompilerFromVersion v

_ -> Left $ stringException "Only GHC is supported by stack --nix"

-- Exceptions thown specifically by Stack.Nix

data StackNixException

= NixCannotUseShellFileAndPackagesException

-- ^ Nix can't be given packages and a shell file at the same time

deriving (Typeable)

instance Exception StackNixException

instance Show StackNixException where

show NixCannotUseShellFileAndPackagesException =

"You cannot have packages and a shell-file filled at the same time in your nix-shell configuration."