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gf-core/src/GF/Source/CF.hs

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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 conversing them to GF
-----------------------------------------------------------------------------
module GF.Source.CF (getCF) where
import GF.Grammar.Grammar
import GF.Grammar.Macros
import GF.Infra.Ident
import GF.Infra.Modules
import GF.Data.Operations
import Data.Char
import Data.List
import qualified Data.ByteString.Char8 as BS
getCF :: String -> String -> Err SourceGrammar
getCF name = fmap (cf2gf name) . 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 [(init fun, (cat, map mkIt its))]
cat : a : its | isArrow a ->
Ok [(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 = (CFFun, (CFCat, [CFItem]))
type CFItem = Either CFCat String
type CFCat = String
type CFFun = String
--------------------------
-- the compiler ----------
--------------------------
cf2gf :: String -> CF -> SourceGrammar
cf2gf name cf = MGrammar [
(aname, ModMod (emptyModule {mtype = MTAbstract, jments = abs})),
(cname, ModMod (emptyModule {mtype = MTConcrete aname, jments = cnc}))
]
where
(abs,cnc) = cf2grammar cf
aname = identS $ name ++ "Abs"
cname = identS name
cf2grammar :: CF -> (BinTree Ident Info, BinTree Ident Info)
cf2grammar rules = (buildTree abs, buildTree conc) where
abs = cats ++ funs
conc = lincats ++ lins
cats = [(cat, AbsCat (yes []) (yes [])) |
cat <- nub (concat (map cf2cat rules))] ----notPredef cat
lincats = [(cat, CncCat (yes defLinType) nope nope) | (cat,AbsCat _ _) <- cats]
(funs,lins) = unzip (map cf2rule rules)
cf2cat :: CFRule -> [Ident]
cf2cat (_,(cat, items)) = map identS $ cat : [c | Left c <- items]
cf2rule :: CFRule -> ((Ident,Info),(Ident,Info))
cf2rule (fun, (cat, items)) = (def,ldef) where
f = identS fun
def = (f, AbsFun (yes (mkProd (args', Cn (identS cat), []))) nope)
args0 = zip (map (identS . ("x" ++) . show) [0..]) items
args = [(v, Cn (identS c)) | (v, Left c) <- args0]
args' = [(identS "_", Cn (identS c)) | (_, Left c) <- args0]
ldef = (f, CncFun
Nothing
(yes (mkAbs (map fst args)
(mkRecord (const theLinLabel) [foldconcat (map mkIt args0)])))
nope)
mkIt (v, Left _) = P (Vr v) theLinLabel
mkIt (_, Right a) = K a
foldconcat [] = K ""
foldconcat tt = foldr1 C tt
identS = identC . BS.pack