Files
gf-core/src/compiler/GF/Grammar/CF.hs

132 lines
4.1 KiB
Haskell

----------------------------------------------------------------------
-- |
-- Module : CF
-- Maintainer : AR
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/11/15 17:56:13 $
-- > CVS $Author: aarne $
-- > CVS $Revision: 1.13 $
--
-- parsing CF grammars and converting them to GF
-----------------------------------------------------------------------------
module GF.Grammar.CF (getCF,CFItem,CFCat,CFFun,cf2gf,CFRule) where
import GF.Grammar.Grammar
import GF.Grammar.Macros
import GF.Infra.Ident
import GF.Infra.Option
import GF.Infra.UseIO
import GF.Data.Operations
import GF.Data.Utilities (nub')
import Data.Char
import Data.List
import qualified Data.ByteString.Char8 as BS
import System.FilePath
getCF :: FilePath -> String -> Err SourceGrammar
getCF fpath = fmap (cf2gf fpath) . pCF
---------------------
-- the parser -------
---------------------
pCF :: String -> Err CF
pCF s = do
rules <- mapM getCFRule $ filter isRule $ lines s
return $ concat rules
where
isRule line = case dropWhile isSpace line of
'-':'-':_ -> False
_ -> not $ all isSpace line
-- rules have an amazingly easy parser, if we use the format
-- fun. C -> item1 item2 ... where unquoted items are treated as cats
-- Actually would be nice to add profiles to this.
getCFRule :: String -> Err [CFRule]
getCFRule s = getcf (wrds s) where
getcf ws = case ws of
fun : cat : a : its | isArrow a ->
Ok [L NoLoc (init fun, (cat, map mkIt its))]
cat : a : its | isArrow a ->
Ok [L NoLoc (mkFun cat it, (cat, map mkIt it)) | it <- chunk its]
_ -> Bad (" invalid rule:" +++ s)
isArrow a = elem a ["->", "::="]
mkIt w = case w of
('"':w@(_:_)) -> Right (init w)
_ -> Left w
chunk its = case its of
[] -> [[]]
_ -> chunks "|" its
mkFun cat its = case its of
[] -> cat ++ "_"
_ -> concat $ intersperse "_" (cat : map clean its) -- CLE style
clean = filter isAlphaNum -- to form valid identifiers
wrds = takeWhile (/= ";") . words -- to permit semicolon in the end
type CF = [CFRule]
type CFRule = L (CFFun, (CFCat, [CFItem]))
type CFItem = Either CFCat String
type CFCat = String
type CFFun = String
--------------------------
-- the compiler ----------
--------------------------
cf2gf :: FilePath -> CF -> SourceGrammar
cf2gf fpath cf = mGrammar [
(aname, ModInfo MTAbstract MSComplete (modifyFlags (\fs -> fs{optStartCat = Just cat})) [] Nothing [] [] fpath Nothing abs),
(cname, ModInfo (MTConcrete aname) MSComplete noOptions [] Nothing [] [] fpath Nothing cnc)
]
where
name = justModuleName fpath
(abs,cnc,cat) = cf2grammar cf
aname = identS $ name ++ "Abs"
cname = identS name
cf2grammar :: CF -> (BinTree Ident Info, BinTree Ident Info, String)
cf2grammar rules = (buildTree abs, buildTree conc, cat) where
abs = cats ++ funs
conc = lincats ++ lins
cat = case rules of
(L _ (_,(c,_))):_ -> c -- the value category of the first rule
_ -> error "empty CF"
cats = [(cat, AbsCat (Just (L NoLoc []))) |
cat <- nub' (concat (map cf2cat rules))] ----notPredef cat
lincats = [(cat, CncCat (Just (L loc defLinType)) Nothing Nothing Nothing) | (cat,AbsCat (Just (L loc _))) <- cats]
(funs,lins) = unzip (map cf2rule rules)
cf2cat :: CFRule -> [Ident]
cf2cat (L loc (_,(cat, items))) = map identS $ cat : [c | Left c <- items]
cf2rule :: CFRule -> ((Ident,Info),(Ident,Info))
cf2rule (L loc (fun, (cat, items))) = (def,ldef) where
f = identS fun
def = (f, AbsFun (Just (L loc (mkProd args' (Cn (identS cat)) []))) Nothing Nothing (Just True))
args0 = zip (map (identS . ("x" ++) . show) [0..]) items
args = [((Explicit,v), Cn (identS c)) | (v, Left c) <- args0]
args' = [(Explicit,identS "_", Cn (identS c)) | (_, Left c) <- args0]
ldef = (f, CncFun
Nothing
(Just (L loc (mkAbs (map fst args)
(mkRecord (const theLinLabel) [foldconcat (map mkIt args0)]))))
Nothing
Nothing)
mkIt (v, Left _) = P (Vr v) theLinLabel
mkIt (_, Right a) = K a
foldconcat [] = K ""
foldconcat tt = foldr1 C tt
identS = identC . BS.pack