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|
----------------------------------------------------------------------
-- |
-- Maintainer : PL
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/04/21 16:22:58 $
-- > CVS $Author: bringert $
-- > CVS $Revision: 1.2 $
--
-- Converting SimpleGFC grammars to MCFG grammars, nondeterministically.
--
-- the resulting grammars might be /very large/
--
-- the conversion is only equivalent if the GFC grammar has a context-free backbone.
-----------------------------------------------------------------------------
module GF.OldParsing.ConvertSimpleToMCFG.Nondet (convertGrammar) where
import GF.System.Tracing
import GF.Printing.PrintParser
import GF.Printing.PrintSimplifiedTerm
-- import PrintGFC
-- import qualified PrGrammar as PG
import Control.Monad
-- import Ident (Ident(..))
import qualified GF.Canon.AbsGFC as AbsGFC
-- import GFC
import GF.Canon.Look
import GF.Data.Operations
-- import qualified Modules as M
import GF.Canon.CMacros (defLinType)
-- import MkGFC (grammar2canon)
import GF.OldParsing.Utilities
-- import GF.OldParsing.GrammarTypes
import GF.Data.SortedList
import qualified GF.OldParsing.MCFGrammar as MCF (Grammar, Rule(..), Lin(..))
import GF.OldParsing.SimpleGFC
-- import Maybe (listToMaybe)
import Data.List (groupBy) -- , transpose)
import GF.Data.BacktrackM
----------------------------------------------------------------------
--convertGrammar :: Grammar -> MCF.Grammar
convertGrammar rules = tracePrt "#mcf-rules total" (prt . length) $
solutions conversion rules undefined
where conversion = member rules >>= convertRule
--convertRule :: Rule -> CnvMonad MCF.Rule
convertRule (Rule fun (cat :@ _, decls) (Just (term, ctype)))
= do let args = [ arg | _ ::: (arg :@ _) <- decls ]
writeState (initialMCat cat, map initialMCat args, [])
convertTerm cat term
(newCat, newArgs, linRec) <- readState
let newTerm = map (instLin newArgs) linRec
return (MCF.Rule newCat newArgs newTerm fun)
convertRule _ = failure
instLin newArgs (MCF.Lin lbl lin) = MCF.Lin lbl (map instSym lin)
where instSym = mapSymbol instCat id
instCat (_, lbl, arg) = (newArgs !! arg, lbl, arg)
--convertTerm :: Cat -> Term -> CnvMonad ()
convertTerm cat term = do rterm <- simplifyTerm term
env <- readEnv
let ctype = lookupCType env cat
reduce ctype rterm emptyPath
------------------------------------------------------------
{-
type CnvMonad a = BacktrackM Grammar CMRule a
type CMRule = (MCFCat, [MCFCat], LinRec)
type LinRec = [Lin Cat Path Tokn]
-}
--initialMCat :: Cat -> MCFCat
initialMCat cat = (cat, []) --MCFCat cat []
----------------------------------------------------------------------
--simplifyTerm :: Term -> CnvMonad STerm
simplifyTerm (con :^ terms) = liftM (con :^) $ mapM simplifyTerm terms
simplifyTerm (Rec record) = liftM Rec $ mapM simplifyAssign record
simplifyTerm (term :. lbl) = liftM (+. lbl) $ simplifyTerm term
simplifyTerm (Tbl table) = Tbl $ mapM simplifyCase table
simplifyTerm (term :! sel)
= do sterm <- simplifyTerm term
ssel <- simplifyTerm sel
case sterm of
Tbl table -> do (pat, val) <- member table
pat =?= ssel
return val
_ -> do sel' <- expandTerm ssel
return (sterm +! sel')
simplifyTerm (Variants terms) = liftM Variants $ mapM simplifyTerm terms
simplifyTerm (term1 :++ term2) = liftM2 (:++) (simplifyTerm term1) (simplifyTerm term2)
simplifyTerm term = return term
-- error constructors:
-- (I CIdent) - from resource
-- (LI Ident) - pattern variable
-- (EInt Integer) - integer
--simplifyAssign :: Assign -> CnvMonad (Label, STerm)
simplifyAssign (lbl, term) = liftM ((,) lbl) $ simplifyTerm term
--simplifyCase :: Case -> [CnvMonad (STerm, STerm)]
simplifyCase (pat, term) = liftM2 (,) (simplifyTerm pat) (simplifyTerm term)
------------------------------------------------------------
-- reducing simplified terms, collecting mcf rules
--reduce :: CType -> STerm -> Path -> CnvMonad ()
reduce StrT term path = updateLin (path, term)
reduce (ConT _) term path
= do pat <- expandTerm term
updateHead (path, pat)
reduce ctype (Variants terms) path
= do term <- member terms
reduce ctype term path
reduce (RecT rtype) term path
= sequence_ [ reduce ctype (term +. lbl) (path ++. lbl) |
(lbl, ctype) <- rtype ]
reduce (TblT _ ctype) (Tbl table) path
= sequence_ [ reduce ctype term (path ++! pat) |
(pat, term) <- table ]
reduce (TblT ptype vtype) arg@(Arg _ _ _) path
= do env <- readEnv
sequence_ [ reduce vtype (arg +! pat) (path ++! pat) |
pat <- groundTerms ptype ]
reduce ctype term path = error ("reduce:\n ctype = (" ++ show ctype ++
")\n term = (" ++ show term ++
")\n path = (" ++ show path ++ ")\n")
------------------------------------------------------------
-- expanding a term to ground terms
--expandTerm :: STerm -> CnvMonad STerm
expandTerm arg@(Arg _ _ _)
= do env <- readEnv
pat <- member $ groundTerms $ cTypeForArg env arg
pat =?= arg
return pat
expandTerm (con :^ terms) = liftM (con :^) $ mapM expandTerm terms
expandTerm (Rec record) = liftM Rec $ mapM expandAssign record
expandTerm (Variants terms) = member terms >>= expandTerm
expandTerm term = error $ "expandTerm: " ++ show term
--expandAssign :: (Label, STerm) -> CnvMonad (Label, STerm)
expandAssign (lbl, term) = liftM ((,) lbl) $ expandTerm term
------------------------------------------------------------
-- unification of patterns and selection terms
--(=?=) :: STerm -> STerm -> CnvMonad ()
Wildcard =?= _ = return ()
Rec precord =?= arg@(Arg _ _ _) = sequence_ [ pat =?= (arg +. lbl) |
(lbl, pat) <- precord ]
pat =?= Arg arg _ path = updateArg arg (path, pat)
(con :^ pats) =?= (con' :^ terms) = do guard (con==con' && length pats==length terms)
sequence_ $ zipWith (=?=) pats terms
Rec precord =?= Rec record = sequence_ [ maybe mzero (pat =?=) mterm |
(lbl, pat) <- precord,
let mterm = lookup lbl record ]
pat =?= term = error $ "(=?=): " ++ show pat ++ " =?= " ++ show term
------------------------------------------------------------
-- updating the mcf rule
--updateArg :: Int -> Constraint -> CnvMonad ()
updateArg arg cn
= do (head, args, lins) <- readState
args' <- updateNth (addToMCFCat cn) arg args
writeState (head, args', lins)
--updateHead :: Constraint -> CnvMonad ()
updateHead cn
= do (head, args, lins) <- readState
head' <- addToMCFCat cn head
writeState (head', args, lins)
--updateLin :: Constraint -> CnvMonad ()
updateLin (path, term)
= do let newLins = term2lins term
(head, args, lins) <- readState
let lins' = lins ++ map (MCF.Lin path) newLins
writeState (head, args, lins')
--term2lins :: STerm -> [[Symbol (Cat, Path, Int) Tokn]]
term2lins (Arg arg cat path) = return [Cat (cat, path, arg)]
term2lins (Token str) = return [Tok str]
term2lins (t1 :++ t2) = liftM2 (++) (term2lins t1) (term2lins t2)
term2lins (Empty) = return []
term2lins (Variants terms) = terms >>= term2lins
term2lins term = error $ "term2lins: " ++ show term
--addToMCFCat :: Constraint -> MCFCat -> CnvMonad MCFCat
addToMCFCat cn ({-MCFCat-} cat, cns) = liftM ({-MCFCat-} (,) cat) $ addConstraint cn cns
--addConstraint :: Constraint -> [Constraint] -> CnvMonad [Constraint]
addConstraint cn0 (cn : cns)
| fst cn0 > fst cn = liftM (cn:) (addConstraint cn0 cns)
| fst cn0 == fst cn = guard (snd cn0 == snd cn) >>
return (cn : cns)
addConstraint cn0 cns = return (cn0 : cns)
----------------------------------------------------------------------
-- utilities
updateNth :: Monad m => (a -> m a) -> Int -> [a] -> m [a]
updateNth update 0 (a : as) = liftM (:as) (update a)
updateNth update n (a : as) = liftM (a:) (updateNth update (n-1) as)
--lookupCType :: GrammarEnv -> Cat -> CType
lookupCType env cat = errVal defLinType $
lookupLincat (fst env) (AbsGFC.CIQ (snd env) cat)
--groundTerms :: GrammarEnv -> CType -> [STerm]
groundTerms env ctype = err error (map term2spattern) $
allParamValues (fst env) ctype
--cTypeForArg :: GrammarEnv -> STerm -> CType
cTypeForArg env (Arg nr cat (Path path))
= follow path $ lookupCType env cat
where follow [] ctype = ctype
follow (Right pat : path) (TblT _ ctype) = follow path ctype
follow (Left lbl : path) (RecT rec)
= case [ ctype | (lbl', ctype) <- rec, lbl == lbl' ] of
[ctype] -> follow path ctype
err -> error $ "follow: " ++ show rec ++ " . " ++ show lbl ++
" results in " ++ show err
term2spattern (AbsGFC.R rec) = Rec [ (lbl, term2spattern term) |
AbsGFC.Ass lbl term <- rec ]
term2spattern (AbsGFC.Con con terms) = con :^ map term2spattern terms
|
