src/AST/PrettyPrint.hs · elk

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elk/src/AST/PrettyPrint.hs

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1{-# LANGUAGE FlexibleInstances #-}

2module AST.PrettyPrint where

4import Control.Monad.Trans.Error

5import Text.PrettyPrint as P

6import qualified AST.Helpers as Help

9class Pretty a where

10 pretty :: a -> Doc

13instance Pretty Doc where

14 pretty doc = doc

17instance Pretty String where

18 pretty = P.text

21renderPretty :: (Pretty a) => a -> String

22renderPretty e =

23 render (pretty e)

26commaCat :: [Doc] -> Doc

27commaCat docs =

28 cat (punctuate comma docs)

31commaSep :: [Doc] -> Doc

32commaSep docs =

33 sep (punctuate comma docs)

36parensIf :: Bool -> Doc -> Doc

37parensIf bool doc =

38 if bool then parens doc else doc

41variable :: String -> Doc

42variable x =

43 if Help.isOp x then parens (text x) else text x

46eightyCharLines :: Int -> String -> String

47eightyCharLines indent message = answer

48 where

49 (answer,_,_) = foldl step (spaces, indent-1, "") chunks

51 chunks = map (\w -> (w, length w)) (words message)

52 spaces = replicate indent ' '

53 step (sentence, slen, space) (word, wlen)

54 | slen + wlen > 79 = (sentence ++ "\n" ++ spaces ++ word, indent + wlen, " ")

55 | otherwise = (sentence ++ space ++ word, slen + wlen + length space, " ")

58instance Error Doc where

59 noMsg = P.empty

60 strMsg = P.text

63instance ErrorList Doc where

64 listMsg str = [ P.text str ]