Types.hs

{-# LANGUAGE InstanceSigs #-}

-- | Core types for the scfg configuration file format.
module Data.Scfg.Types (
  Directive (..),
  Config,
  ParseError (..),
) where

import Control.Exception (Exception (..))
import Data.Text (Text)
import qualified Data.Text as T

{- | A directive: a name, zero or more parameteres, and zero or more
child directives.
-}
data Directive = Directive
  { directiveName :: Text
  , directiveParams :: [Text]
  , directiveChildren :: [Directive]
  }
  deriving (Show, Eq)

-- | A parsed scfg configuration: a list of top-level directives.
type Config = [Directive]

-- | An error that occurred while parsing a scfg configuration.
data ParseError = ParseError
  { errorLine :: Int
  -- ^ Line number of parse error
  , errorColumn :: Int
  -- ^ Column number of parse error
  , errorMessage :: Text
  -- ^ Human-readable error message describing the parse error
  }
  deriving (Show, Eq)

instance Exception ParseError where
  displayException :: ParseError -> String
  displayException = T.unpack . errorMessage