Files
gf-core/src/GF/Conversion/SimpleToFinite.hs
2005-04-11 12:57:45 +00:00

135 lines
4.6 KiB
Haskell

----------------------------------------------------------------------
-- |
-- Maintainer : PL
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/04/11 13:52:48 $
-- > CVS $Author: peb $
-- > CVS $Revision: 1.1 $
--
-- Calculating the finiteness of each type in a grammar
-----------------------------------------------------------------------------
module GF.Conversion.SimpleToFinite
(convertGrammar) where
import GF.System.Tracing
import GF.Infra.Print
import GF.Formalism.GCFG
import GF.Formalism.SimpleGFC
import GF.Data.SortedList
import GF.Data.Assoc
import GF.Data.BacktrackM
import GF.Data.Utilities (lookupList)
import Ident (Ident(..))
type CnvMonad a = BacktrackM () a
convertGrammar :: SimpleGrammar -> SimpleGrammar
convertGrammar rules = tracePrt "#finite simpleGFC rules" (prt . length) $
solutions cnvMonad ()
where split = calcSplitable rules
cnvMonad = member rules >>= convertRule split
convertRule :: Splitable -> SimpleRule -> CnvMonad SimpleRule
convertRule split (Rule abs cnc)
= do newAbs <- convertAbstract split abs
return $ Rule newAbs cnc
convertAbstract :: Splitable -> Abstract Decl Name -> CnvMonad (Abstract Decl Name)
convertAbstract split (Abs (_ ::: typ) decls fun)
= case splitableFun split fun of
Just newCat -> return $ Abs (anyVar ::: (newCat :@ [])) decls fun
Nothing -> expandTyping split fun [] typ decls []
expandTyping :: Splitable -> Name -> [(Var, Cat)] -> Type -> [Decl] -> [Decl]
-> CnvMonad (Abstract Decl Name)
expandTyping split fun env (cat :@ atoms) [] decls
= return $ Abs decl (reverse decls) fun
where decl = anyVar ::: substAtoms split env cat atoms []
expandTyping split fun env typ ((x ::: (xcat :@ xatoms)) : declsToDo) declsDone
= do (xcat', env') <- calcNewEnv
let decl = x ::: substAtoms split env xcat' xatoms []
expandTyping split fun env' typ declsToDo (decl : declsDone)
where calcNewEnv = case splitableCat split xcat of
Just newCats -> do newCat <- member newCats
return (newCat, (x,newCat) : env)
Nothing -> return (xcat, env)
substAtoms :: Splitable -> [(Var, Cat)] -> Cat -> [Atom] -> [Atom] -> Type
substAtoms split env cat [] atoms = cat :@ reverse atoms
substAtoms split env cat (atom:atomsToDo) atomsDone
= case atomLookup split env atom of
Just newCat -> substAtoms split env (mergeArg cat newCat) atomsToDo atomsDone
Nothing -> substAtoms split env cat atomsToDo (atom : atomsDone)
atomLookup split env (AVar x) = lookup x env
atomLookup split env (ACon con) = splitableFun split (constr2name con)
----------------------------------------------------------------------
-- splitable categories (finite, no dependencies)
-- they should also be used as some dependency
type Splitable = (Assoc Cat [Cat], Assoc Name Cat)
splitableCat :: Splitable -> Cat -> Maybe [Cat]
splitableCat = lookupAssoc . fst
splitableFun :: Splitable -> Name -> Maybe Cat
splitableFun = lookupAssoc . snd
calcSplitable :: [SimpleRule] -> Splitable
calcSplitable rules = (listAssoc splitableCat2Funs, listAssoc splitableFun2Cat)
where splitableCat2Funs = groupPairs $ nubsort
[ (cat, mergeFun fun cat) | (cat, fun) <- splitableCatFuns ]
splitableFun2Cat = nubsort
[ (fun, mergeFun fun cat) | (cat, fun) <- splitableCatFuns ]
-- cat-fun pairs that are splitable
splitableCatFuns = [ (cat, fun) |
Rule (Abs (_ ::: (cat :@ [])) [] fun) _ <- rules,
splitableCats ?= cat ]
-- all cats that are splitable
splitableCats = listSet $
tracePrt "finite categories to split" prt $
(nondepCats <**> depCats) <\\> resultCats
-- all result cats for some pure function
resultCats = nubsort [ cat | Rule (Abs (_ ::: (cat :@ _)) decls _) _ <- rules,
not (null decls) ]
-- all cats in constants without dependencies
nondepCats = nubsort [ cat | Rule (Abs (_ ::: (cat :@ [])) [] _) _ <- rules ]
-- all cats occurring as some dependency of another cat
depCats = nubsort [ cat | Rule (Abs decl decls _) _ <- rules,
cat <- varCats [] (decls ++ [decl]) ]
varCats _ [] = []
varCats env ((x ::: (xcat :@ atoms)) : decls)
= varCats ((x,xcat) : env) decls ++
[ cat | AVar y <- atoms, cat <- lookupList y env ]
----------------------------------------------------------------------
-- utilities
-- mergeing categories
mergeCats :: String -> String -> String -> Cat -> Cat -> Cat
mergeCats before middle after (IC cat) (IC arg)
= IC (before ++ cat ++ middle ++ arg ++ after)
mergeFun, mergeArg :: Cat -> Cat -> Cat
mergeFun = mergeCats "{" ":" "}"
mergeArg = mergeCats "" "" ""