Files
gf-core/src/GF/Parsing/ConvertGFCtoMCFG/Strict.hs
2005-03-29 10:17:53 +00:00

196 lines
7.4 KiB
Haskell

----------------------------------------------------------------------
-- |
-- Module : ConvertGFCtoMCFG.Strict
-- Maintainer : PL
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/03/29 11:17:55 $
-- > CVS $Author: peb $
-- > CVS $Revision: 1.2 $
--
-- Converting GFC 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.
-- (also, the conversion might fail if the GFC grammar has dependent or higher-order types)
-----------------------------------------------------------------------------
module GF.Parsing.ConvertGFCtoMCFG.Strict (convertGrammar) where
import GF.System.Tracing
-- import IOExts (unsafePerformIO)
import GF.Printing.PrintParser
import GF.Printing.PrintSimplifiedTerm
-- import PrintGFC
-- import qualified PrGrammar as PG
import Monad
import Ident (Ident(..))
import AbsGFC
import GFC
import Look
import Operations
import qualified Modules as M
import CMacros (defLinType)
import MkGFC (grammar2canon)
import GF.Parsing.Utilities
import GF.Parsing.GrammarTypes
import GF.Parsing.MCFGrammar (Grammar, Rule(..), Lin(..))
import GF.Data.SortedList
-- import Maybe (listToMaybe)
import List (groupBy) -- , transpose)
import GF.Data.BacktrackM
----------------------------------------------------------------------
type GrammarEnv = (CanonGrammar, Ident)
convertGrammar :: GrammarEnv -- ^ the canonical grammar, together with the selected language
-> MCFGrammar -- ^ the resulting MCF grammar
convertGrammar gram = trace2 "language" (prt (snd gram)) $
trace2 "modules" (prtSep " " modnames) $
tracePrt "#mcf-rules total" (prt . length) $
solutions conversion gram undefined
where Gr modules = grammar2canon (fst gram)
modnames = uncurry M.allExtends gram
conversion = member modules >>= convertModule
convertModule (Mod (MTCnc modname _) _ _ _ defs)
| modname `elem` modnames = member defs >>= convertDef
convertModule _ = failure
convertDef :: Def -> CnvMonad MCFRule
convertDef (CncDFun fun (CIQ _ cat) args term _)
| trace2 "converting function" (prt fun) True
= do env <- readEnv
let ctype = lookupCType env cat
instArgs <- mapM enumerateArg args
let instTerm = substitutePaths env instArgs term
newCat <- emcfCat cat instTerm
newArgs <- mapM (extractArg instArgs) args
let newTerm = strPaths env ctype instTerm >>= extractLin newArgs
traceDot $
return (Rule newCat newArgs newTerm fun)
convertDef _ = failure
------------------------------------------------------------
type CnvMonad a = BacktrackM GrammarEnv () a
----------------------------------------------------------------------
-- strict conversion
extractArg :: [STerm] -> ArgVar -> CnvMonad MCFCat
extractArg args (A cat nr) = emcfCat cat (args !! fromInteger nr)
emcfCat :: Cat -> STerm -> CnvMonad MCFCat
emcfCat cat term = do env <- readEnv
member $ map (MCFCat cat) $ parPaths env (lookupCType env cat) term
enumerateArg :: ArgVar -> CnvMonad STerm
enumerateArg (A cat nr) = do env <- readEnv
let ctype = lookupCType env cat
enumerate (SArg (fromInteger nr) cat emptyPath) ctype
where enumerate arg (TStr) = return arg
enumerate arg ctype@(Cn _) = do env <- readEnv
member $ groundTerms env ctype
enumerate arg (RecType rtype)
= liftM SRec $ sequence [ liftM ((,) lbl) $
enumerate (arg +. lbl) ctype |
lbl `Lbg` ctype <- rtype ]
enumerate arg (Table stype ctype)
= do env <- readEnv
state <- readState
liftM STbl $ sequence [ liftM ((,) sel) $
enumerate (arg +! sel) ctype |
sel <- solutions (enumerate err stype) env state ]
where err = error "enumerate: parameter type should not be string"
-- Substitute each instantiated parameter path for its instantiation
substitutePaths :: GrammarEnv -> [STerm] -> Term -> STerm
substitutePaths env arguments trm = subst trm
where subst (con `Con` terms) = con `SCon` map subst terms
subst (R record) = SRec [ (lbl, subst term) | lbl `Ass` term <- record ]
subst (term `P` lbl) = subst term +. lbl
subst (T ptype table) = STbl [ (pattern2sterm pat, subst term) |
pats `Cas` term <- table, pat <- pats ]
subst (V ptype table) = STbl [ (pat, subst term) |
(pat, term) <- zip (groundTerms env ptype) table ]
subst (term `S` select) = subst term +! subst select
subst (term `C` term') = subst term `SConcat` subst term'
subst (K str) = SToken str
subst (E) = SEmpty
subst (FV terms) = evalFV $ map subst terms
subst (Arg (A _ arg)) = arguments !! fromInteger arg
termPaths :: GrammarEnv -> CType -> STerm -> [(Path, (CType, STerm))]
termPaths env (TStr) term = [ (emptyPath, (TStr, term)) ]
termPaths env (RecType rtype) (SRec record)
= [ (path ++. lbl, value) |
(lbl, term) <- record,
let ctype = lookupLabelling lbl rtype,
(path, value) <- termPaths env ctype term ]
termPaths env (Table _ ctype) (STbl table)
= [ (path ++! pat, value) |
(pat, term) <- table,
(path, value) <- termPaths env ctype term ]
termPaths env ctype (SVariants terms)
= terms >>= termPaths env ctype
termPaths env (Cn pc) term = [ (emptyPath, (Cn pc, term)) ]
{- ^^^ variants are pushed inside (not equivalent -- but see record-variants.txt):
{a=a1; b=b1} | {a=a2; b=b2} ==> {a=a1|a2; b=b1|b2}
[p=>p1;q=>q1] | [p=>p2;q=>q2] ==> [p=>p1|p2;q=>q1|q2]
-}
parPaths :: GrammarEnv -> CType -> STerm -> [[(Path, STerm)]]
parPaths env ctype term = mapM (uncurry (map . (,))) (groupPairs paths)
where paths = nubsort [ (path, value) | (path, (Cn _, value)) <- termPaths env ctype term ]
strPaths :: GrammarEnv -> CType -> STerm -> [(Path, STerm)]
strPaths env ctype term = [ (path, evalFV values) | (path, values) <- groupPairs paths ]
where paths = nubsort [ (path, value) | (path, (TStr, value)) <- termPaths env ctype term ]
extractLin :: [MCFCat] -> (Path, STerm) -> [Lin MCFCat MCFLabel Tokn]
extractLin args (path, term) = map (Lin path) (convertLin term)
where convertLin (t1 `SConcat` t2) = liftM2 (++) (convertLin t1) (convertLin t2)
convertLin (SEmpty) = [[]]
convertLin (SToken tok) = [[Tok tok]]
convertLin (SVariants terms) = concatMap convertLin terms
convertLin (SArg nr _ path) = [[Cat (args !! nr, path, nr)]]
evalFV terms0 = case nubsort (concatMap flattenFV terms0) of
[term] -> term
terms -> SVariants terms
where flattenFV (SVariants ts) = ts
flattenFV t = [t]
----------------------------------------------------------------------
-- utilities
lookupCType :: GrammarEnv -> Cat -> CType
lookupCType env cat = errVal defLinType $
lookupLincat (fst env) (CIQ (snd env) cat)
lookupLabelling :: Label -> [Labelling] -> CType
lookupLabelling lbl rtyp = case [ ctyp | lbl' `Lbg` ctyp <- rtyp, lbl == lbl' ] of
[ctyp] -> ctyp
err -> error $ "lookupLabelling:" ++ show err
groundTerms :: GrammarEnv -> CType -> [STerm]
groundTerms env ctype = err error (map term2spattern) $
allParamValues (fst env) ctype
term2spattern (R rec) = SRec [ (lbl, term2spattern term) | Ass lbl term <- rec ]
term2spattern (Con con terms) = SCon con $ map term2spattern terms
pattern2sterm :: Patt -> STerm
pattern2sterm (con `PC` patterns) = con `SCon` map pattern2sterm patterns
pattern2sterm (PR record) = SRec [ (lbl, pattern2sterm pattern) |
lbl `PAss` pattern <- record ]