{-# OPTIONS -fno-warn-incomplete-patterns #-}
-- The above warning supression flag is a temporary kludge.
-- While working on this module you are encouraged to remove it and fix
-- any warnings in the module. See
--     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
-- for details
{-# LANGUAGE DeriveDataTypeable #-}

module HsImpExp where

import Module		( ModuleName )
import HsDoc		( HsDocString )

import Outputable
import FastString
import SrcLoc		( Located(..) )

import Data.Data

type LImportDecl name = Located (ImportDecl name)

-- | A single Haskell @import@ declaration.
data ImportDecl name
  = ImportDecl {
      ideclName      :: Located ModuleName, -- ^ Module name.
      ideclPkgQual   :: Maybe FastString,   -- ^ Package qualifier.
      ideclSource    :: Bool,               -- ^ True <=> {-# SOURCE #-} import
      ideclQualified :: Bool,               -- ^ True => qualified
      ideclAs        :: Maybe ModuleName,   -- ^ as Module
      ideclHiding    :: Maybe (Bool, [LIE name]) -- ^ (True => hiding, names)
    } deriving (Data, Typeable)

instance (Outputable name) => Outputable (ImportDecl name) where
    ppr (ImportDecl mod pkg from qual as spec)
      = hang (hsep [ptext (sLit "import"), ppr_imp from, 
                    pp_qual qual, pp_pkg pkg, ppr mod, pp_as as])
	     4 (pp_spec spec)
      where
        pp_pkg Nothing  = empty
        pp_pkg (Just p) = doubleQuotes (ftext p)

	pp_qual False   = empty
	pp_qual True	= ptext (sLit "qualified")

	pp_as Nothing   = empty
	pp_as (Just a)  = ptext (sLit "as") <+> ppr a

	ppr_imp True  = ptext (sLit "{-# SOURCE #-}")
	ppr_imp False = empty

	pp_spec Nothing             = empty
	pp_spec (Just (False, ies)) = ppr_ies ies
	pp_spec (Just (True,  ies)) = ptext (sLit "hiding") <+> ppr_ies ies

	ppr_ies []  = ptext (sLit "()")
	ppr_ies ies = char '(' <+> interpp'SP ies <+> char ')'

type LIE name = Located (IE name)

-- | Imported or exported entity.
data IE name
  = IEVar               name
  | IEThingAbs          name		 -- ^ Class/Type (can't tell)
  | IEThingAll          name		 -- ^ Class/Type plus all methods/constructors
  | IEThingWith         name [name]	 -- ^ Class/Type plus some methods/constructors
  | IEModuleContents    ModuleName	 -- ^ (Export Only)
  | IEGroup             Int HsDocString  -- ^ Doc section heading
  | IEDoc               HsDocString      -- ^ Some documentation
  | IEDocNamed          String           -- ^ Reference to named doc
  deriving (Data, Typeable)

ieName :: IE name -> name
ieName (IEVar n) 	 = n
ieName (IEThingAbs  n)   = n
ieName (IEThingWith n _) = n
ieName (IEThingAll  n)   = n

ieNames :: IE a -> [a]
ieNames (IEVar            n   ) = [n]
ieNames (IEThingAbs       n   ) = [n]
ieNames (IEThingAll       n   ) = [n]
ieNames (IEThingWith      n ns) = n:ns
ieNames (IEModuleContents _   ) = []
ieNames (IEGroup          _ _ ) = []
ieNames (IEDoc            _   ) = []
ieNames (IEDocNamed       _   ) = []        

instance (Outputable name) => Outputable (IE name) where
    ppr (IEVar	        var)	= pprHsVar var
    ppr (IEThingAbs	thing)	= ppr thing
    ppr (IEThingAll	thing)	= hcat [ppr thing, text "(..)"]
    ppr (IEThingWith thing withs)
	= ppr thing <> parens (fsep (punctuate comma (map pprHsVar withs)))
    ppr (IEModuleContents mod)
	= ptext (sLit "module") <+> ppr mod
    ppr (IEGroup n _)           = text ("<IEGroup: " ++ (show n) ++ ">")
    ppr (IEDoc doc)             = ppr doc
    ppr (IEDocNamed string)     = text ("<IEDocNamed: " ++ string ++ ">")