module Error where

import Data.List (sort)
import Text.Parsec (SourcePos, errorPos)
import Text.Parsec.Error (ParseError, errorMessages, showErrorMessages)

data Error
  = TypeError String SourcePos
  | Error String SourcePos
  deriving (Eq)

instance Show Error where
  show (Error message pos) =
    show pos ++ " error: " ++ message
  -- XXX: can we do this differently?
  show (TypeError message pos) =
    show pos ++ " error: " ++ message

showParserError :: ParseError -> String
showParserError error =
  show (errorPos error) ++ " error: syntax error"
    ++ showErrorMessages "or" "unknown parser error" "   expecting" "  unexpected" "end of input" (errorMessages error)

instance Ord Error where
  compare (Error _ pos1) (Error _ pos2) = compare pos1 pos2

showErrorList :: [Error] -> String
showErrorList errs = unlines $ map show (sort errs)