{- |

Module : $Header$

Description : create legal Haskell identifiers

Copyright : (c) C.Maeder, Uni Bremen 2003 - 2004

License : GPLv2 or higher, see LICENSE.txt

Maintainer : Christian.Maeder@dfki.de

Stability : experimental

Portability : portable

Translation of identifiers to Haskell.

-}

module Haskell.TranslateId (IdCase (..), translateIdWithType) where

import Common.Id

import qualified Data.Map as Map

import qualified Data.Set as Set

import Data.Char

-- | Converts an identifier to a valid lower or upper case Haskell name

translateIdWithType :: IdCase -> Id -> String

translateIdWithType ty i =

let s = translateId i ""

c = if null s then error "translateIdWithTyper" else head s

in case ty of

UpperId ->

if isLower c || c == '_' || isDigit c

then "A__" ++ s else s

LowerId ->

if isUpper c || c == '_' || isDigit c || s `Set.member` lowerCaseList

then "a__" ++ s else s

-- reserved Haskell keywords

lowerCaseList :: Set.Set String

lowerCaseList = Set.fromList [

"case", "class", "data", "default", "deriving", "do", "else",

"if", "import", "in", "infix", "infixl", "infixr", "instance",

"let", "module", "newtype", "of", "then", "type", "where"]

-- | Letter case indicator

data IdCase = UpperId | LowerId

-- | Converts an identifier to a valid Haskell name

translateId :: Id -> ShowS

translateId (Id tlist idlist _) =

showSepList id translateToken tlist . translateCompound idlist

-- | Translate a 'Token' according to the 'symbolMapping'.

translateToken :: Token -> ShowS

translateToken t = let str = tokStr t in showString $

if isPlace t then "_2"

else if all isDigit str && not (isSingle str) then '_' : str

else if head str == '\'' then

"_3" ++ concatMap (('_' :) . show . ord) (tail str) ++ "_X"

else concatMap symbolMapping str

-- | Translate a compound list

translateCompound :: [Id] -> ShowS

-- [ , ]

translateCompound ids = noShow (null ids) $ showString "_F"

. showSepList (showString "_K") translateId ids

. showString "_J"

{- | Converts characters to parts of Haskell identifiers

thereby translating special ones -}

symbolMapping :: Char -> String

symbolMapping c = Map.findWithDefault [c] c $ Map.fromList

{- avoid compound symbols and keep map injective

Special / reserved -}

[('_' , "_1"), -- \95

('{' , "_b"), -- \123

('}' , "_r"), -- \125

('[' , "_s"), -- \91

(']' , "_q"), -- \93

('.' , "_d"), -- \46

('\'', "_p"),

-- Symbols

('+' , "_P"), -- \43

('-' , "_M"), -- \45

('*' , "_T"), -- \42

('/' , "_S"), -- \47

('\\', "_B"), -- \92

('&' , "_A"), -- \38

('=' , "_E"), -- \61

('<' , "_L"), -- \60

('>' , "_G"), -- \62

('!' , "_R"), -- \33

('?' , "_Q"), -- \63

(':' , "_C"), -- \58

('$' , "_D"), -- \36

('@' , "_O"), -- \64

('#' , "_H"), -- \35

('^' , "_V"), -- \94

('|' , "_I"), -- \124

('~' , "_N"), -- \126

('\161', "_e"),

('\162', "_c"),

('\163', "_l"),

('\167', "_f"),

('\169', "_a"),

('\172', "_n"),

('\176', "_h"),

('\177', "_k"),

('\178', "_w"),

('\179', "_t"),

('\181', "_y"),

('\182', "_j"),

('\183', "_i"),

('\185', "_o"),

('\191', "_u"),

('\215', "_m"),

('\247', "_g")]