{-# LANGUAGE DeriveAnyClass #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE OverloadedStrings #-}
module Data.Dependency.Error ( ResolveError (..)
, DepM
) where
import Control.DeepSeq
import GHC.Generics (Generic)
import Text.PrettyPrint.ANSI.Leijen
type DepM = Either ResolveError
data ResolveError = InternalError
| NotPresent String
| Conflicts [String] String
| CircularDependencies String String
deriving (Show, Eq, NFData, Generic)
instance Pretty ResolveError where
pretty InternalError = red "Error:" <+> "the" <+> squotes "dependency" <+> "package enountered an internal error. Please report this as a bug:\n" <> hang 2 "https://hub.darcs.net/vmchale/ats/issues"
pretty (NotPresent s) = red "Error:" <+> "the package" <+> squotes (text s) <+> "could not be found.\n"
pretty (Conflicts ss s) = red "Error:" <+> "the package" <+> squotes (text s) <+> "conflicts with already in-scope packages: " <+> mconcat (punctuate ", " (fmap (squotes . text) ss))
pretty (CircularDependencies s s') = red "Error:" <+> "package" <+> squotes (text s) <+> "and package" <+> squotes (text s') <+> "form a cycle of dependencies"