----------------------------------------------------------------------
-- |
-- Module      : GFCCAPI
-- Maintainer  : Aarne Ranta
-- Stability   : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 
-- > CVS $Author: 
-- > CVS $Revision: 
--
-- Reduced Application Programmer's Interface to GF, meant for
-- embedded GF systems. AR 19/9/2007
-----------------------------------------------------------------------------

module  GF.Canon.GFCC.GFCCAPI where

import GF.Canon.GFCC.DataGFCC
--import GF.Canon.GFCC.GenGFCC
import GF.Canon.GFCC.AbsGFCC
import GF.Canon.GFCC.ParGFCC
import GF.Canon.GFCC.PrintGFCC
import GF.Canon.GFCC.ErrM
--import GF.Data.Operations
--import GF.Infra.UseIO
import qualified Data.Map as Map
import System.Random (newStdGen)
import System.Directory (doesFileExist)
import System

-- This API is meant to be used when embedding GF grammars in Haskell 
-- programs. The embedded system is supposed to use the
-- .gfcm grammar format, which is first produced by the gf program.

---------------------------------------------------
-- Interface
---------------------------------------------------

type MultiGrammar = GFCC
type Language     = String
type Category     = String
type Tree         = Exp

file2grammar :: FilePath -> IO MultiGrammar

linearize    :: MultiGrammar -> Language -> Tree -> String
parse        :: MultiGrammar -> Language -> Category -> String -> [Tree]

linearizeAll     :: MultiGrammar -> Tree -> [String]
linearizeAllLang :: MultiGrammar -> Tree -> [(Language,String)]

--parseAll     :: MultiGrammar -> Category -> String -> [[Tree]]
--parseAllLang :: MultiGrammar -> Category -> String -> [(Language,[Tree])]

readTree   :: MultiGrammar -> String -> Tree
showTree   ::                 Tree -> String

languages  :: MultiGrammar -> [Language]
categories :: MultiGrammar -> [Category]

startCat   :: MultiGrammar -> Category

---------------------------------------------------
-- Implementation
---------------------------------------------------

file2grammar f =
  readFileIf f >>= err (error "no parse") (return . mkGFCC) . pGrammar . myLexer

linearize mgr lang = GF.Canon.GFCC.DataGFCC.linearize mgr (CId lang)


parse mgr lang cat s = [] 
{-
  map tree2exp . 
  errVal [] . 
  parseString (stateOptions sgr) sgr cfcat
 where
   sgr   = stateGrammarOfLang mgr (zIdent lang)
   cfcat = string2CFCat abs cat
   abs   = maybe (error "no abstract syntax") prIdent $ abstract mgr
-}

linearizeAll mgr = map snd . linearizeAllLang mgr
linearizeAllLang mgr t = [(lang,linearThis mgr lang t) | lang <- languages mgr]

{-
parseAll mgr cat = map snd . parseAllLang mgr cat

parseAllLang mgr cat s = 
  [(lang,ts) | lang <- languages mgr, let ts = parse mgr lang cat s, not (null ts)]
-}

readTree _ = err (const exp0) id . (pExp . myLexer)

showTree t = printTree t

languages mgr = [l | CId l <- cncnames mgr]

categories mgr = [c | CId c <- Map.keys (cats (abstract mgr))]

startCat mgr = "S" ----

------------ for internal use only

linearThis = GF.Canon.GFCC.GFCCAPI.linearize

err f g ex = case ex of
  Ok x -> g x
  Bad s -> f s

readFileIf f = do
  b <- doesFileExist f
  if b then readFile f 
       else putStrLn ("file " ++ f ++ " not found") >> return ""