compiler/SourceSyntax/Location.hs · elk

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1{-# LANGUAGE DeriveDataTypeable #-}

2module SourceSyntax.Location where

4import qualified Text.Parsec.Pos as Parsec

5import Data.Data

7data SrcPos = Pos { line :: Int, column :: Int }

8 deriving (Eq, Ord, Data, Typeable)

10data SrcSpan = Span SrcPos SrcPos | NoSpan

11 deriving (Eq, Ord, Data, Typeable)

13data Located e = L SrcSpan e

14 deriving (Eq, Ord, Data, Typeable)

17instance Show SrcPos where

18 show (Pos r c) = "Line " ++ show r ++ ", Column " ++ show c

20instance Show SrcSpan where

21 show span =

22 case span of

23 Span start end -> show start

24 NoSpan -> ""

26instance Show e => Show (Located e) where

27 show (L _ e) = show e

29none = L NoSpan

31at start end = L (Span (Pos (Parsec.sourceLine start) (Parsec.sourceColumn start))

32 (Pos (Parsec.sourceLine end ) (Parsec.sourceColumn end )))

34merge (L s1 _) (L s2 _) = L span

35 where span = case (s1,s2) of

36 (Span start _, Span _ end) -> Span start end

37 (_, NoSpan) -> s1

38 (NoSpan, _) -> s2

40sameAs (L s _) = L s