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gf-core/src/compiler/GF/Grammar/EBNF.hs
hallgren 3814841d7d Eliminate mutual dependencies between the GF compiler and the PGF library 
+ References to modules under src/compiler have been eliminated from the PGF
  library (under src/runtime/haskell). Only two functions had to be moved (from
  GF.Data.Utilities to PGF.Utilities) to make this possible, other apparent
  dependencies turned out to be vacuous.

+ In gf.cabal, the GF executable no longer directly depends on the PGF library
  source directory, but only on the exposed library modules. This means that
  there is less duplication in gf.cabal and that the 30 modules in the
  PGF library will no longer be compiled twice while building GF.

  To make this possible, additional PGF library modules have been exposed, even
  though they should probably be considered for internal use only. They could
  be collected in a PGF.Internal module, or marked as "unstable", to make
  this explicit.

+ Also, by using the -fwarn-unused-imports flag, ~220 redundant imports were
  found and removed, reducing the total number of imports by ~15%.
2013-11-05 13:11:10 +00:00

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----------------------------------------------------------------------
-- |
-- Module : EBNF
-- Maintainer : AR
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/04/21 16:21:13 $
-- > CVS $Author: bringert $
-- > CVS $Revision: 1.5 $
--
-- (Description of the module)
-----------------------------------------------------------------------------
module GF.Grammar.EBNF (getEBNF) where
import GF.Data.Operations
--import GF.Infra.Comments
import GF.Grammar.CF
--import GF.CF.CFIdent
import GF.Grammar.Grammar
--import GF.Grammar.PrGrammar
--import qualified GF.Source.AbsGF as A
import Data.Char
import Data.List
--import System.FilePath
-- AR 18/4/2000 - 31/3/2004
getEBNF :: FilePath -> String -> Err SourceGrammar
getEBNF fpath = fmap (cf2gf fpath . ebnf2cf) . pEBNF
type EBNF = [ERule]
type ERule = (ECat, ERHS)
type ECat = (String,[Int])
type ETok = String
ebnfID = "EBNF" ---- make this parametric!
data ERHS =
ETerm ETok
| ENonTerm ECat
| ESeq ERHS ERHS
| EAlt ERHS ERHS
| EStar ERHS
| EPlus ERHS
| EOpt ERHS
| EEmpty
type CFRHS = [CFItem]
type CFJustRule = (CFCat, CFRHS)
ebnf2cf :: EBNF -> [CFRule]
ebnf2cf ebnf =
[L NoLoc (mkCFF i rule,rule) | (i,rule) <- zip [0..] (normEBNF ebnf)] where
mkCFF i (c, _) = ("Mk" ++ c ++ "_" ++ show i)
normEBNF :: EBNF -> [CFJustRule]
normEBNF erules = let
erules1 = [normERule ([i],r) | (i,r) <- zip [0..] erules]
erules2 = erules1 ---refreshECats erules1 --- this seems to be just bad !
erules3 = concat (map pickERules erules2)
erules4 = nubERules erules3
in [(mkCFCatE cat, map eitem2cfitem its) | (cat,itss) <- erules3, its <- itss]
refreshECats :: [NormERule] -> [NormERule]
refreshECats rules = [recas [i] rule | (i,rule) <- zip [0..] rules] where
recas ii (cat,its) = (updECat ii cat, [recss ii 0 s | s <- its])
recss ii n [] = []
recss ii n (s:ss) = recit (ii ++ [n]) s : recss ii (n+1) ss
recit ii it = case it of
EINonTerm cat -> EINonTerm (updECat ii cat)
EIStar (cat,t) -> EIStar (updECat ii cat, [recss ii 0 s | s <- t])
EIPlus (cat,t) -> EIPlus (updECat ii cat, [recss ii 0 s | s <- t])
EIOpt (cat,t) -> EIOpt (updECat ii cat, [recss ii 0 s | s <- t])
_ -> it
pickERules :: NormERule -> [NormERule]
pickERules rule@(cat,alts) = rule : concat (map pics (concat alts)) where
pics it = case it of
EIStar ru@(cat,t) -> mkEStarRules cat ++ pickERules ru
EIPlus ru@(cat,t) -> mkEPlusRules cat ++ pickERules ru
EIOpt ru@(cat,t) -> mkEOptRules cat ++ pickERules ru
_ -> []
mkEStarRules cat = [(cat', [[],[EINonTerm cat, EINonTerm cat']])]
where cat' = mkNewECat cat "Star"
mkEPlusRules cat = [(cat', [[EINonTerm cat],[EINonTerm cat, EINonTerm cat']])]
where cat' = mkNewECat cat "Plus"
mkEOptRules cat = [(cat', [[],[EINonTerm cat]])]
where cat' = mkNewECat cat "Opt"
nubERules :: [NormERule] -> [NormERule]
nubERules rules = nub optim where
optim = map (substERules (map mkSubst replaces)) irreducibles
(replaces,irreducibles) = partition reducible rules
reducible (cat,[items]) = isNewCat cat && all isOldIt items
reducible _ = False
isNewCat (_,ints) = ints == []
isOldIt (EITerm _) = True
isOldIt (EINonTerm cat) = not (isNewCat cat)
isOldIt _ = False
mkSubst (cat,its) = (cat, head its) -- def of reducible: its must be singleton
--- the optimization assumes each cat has at most one EBNF rule.
substERules :: [(ECat,[EItem])] -> NormERule -> NormERule
substERules g (cat,itss) = (cat, map sub itss) where
sub [] = []
sub (i@(EINonTerm cat') : ii) = case lookup cat g of
Just its -> its ++ sub ii
_ -> i : sub ii
sub (EIStar r : ii) = EIStar (substERules g r) : ii
sub (EIPlus r : ii) = EIPlus (substERules g r) : ii
sub (EIOpt r : ii) = EIOpt (substERules g r) : ii
eitem2cfitem :: EItem -> CFItem
eitem2cfitem it = case it of
EITerm a -> Right a
EINonTerm cat -> Left (mkCFCatE cat)
EIStar (cat,_) -> Left (mkCFCatE (mkNewECat cat "Star"))
EIPlus (cat,_) -> Left (mkCFCatE (mkNewECat cat "Plus"))
EIOpt (cat,_) -> Left (mkCFCatE (mkNewECat cat "Opt"))
type NormERule = (ECat,[[EItem]]) -- disjunction of sequences of items
data EItem =
EITerm String
| EINonTerm ECat
| EIStar NormERule
| EIPlus NormERule
| EIOpt NormERule
deriving Eq
normERule :: ([Int],ERule) -> NormERule
normERule (ii,(cat,rhs)) =
(cat,[map (mkEItem (ii ++ [i])) r' | (i,r') <- zip [0..] (disjNorm rhs)]) where
disjNorm r = case r of
ESeq r1 r2 -> [x ++ y | x <- disjNorm r1, y <- disjNorm r2]
EAlt r1 r2 -> disjNorm r1 ++ disjNorm r2
EEmpty -> [[]]
_ -> [[r]]
mkEItem :: [Int] -> ERHS -> EItem
mkEItem ii rhs = case rhs of
ETerm a -> EITerm a
ENonTerm cat -> EINonTerm cat
EStar r -> EIStar (normERule (ii,(mkECat ii, r)))
EPlus r -> EIPlus (normERule (ii,(mkECat ii, r)))
EOpt r -> EIOpt (normERule (ii,(mkECat ii, r)))
_ -> EINonTerm ("?????",[])
-- _ -> error "should not happen in ebnf" ---
mkECat ints = ("C", ints)
prECat (c,[]) = c
prECat (c,ints) = c ++ "_" ++ prTList "_" (map show ints)
mkCFCatE :: ECat -> CFCat
mkCFCatE = prECat
updECat _ (c,[]) = (c,[])
updECat ii (c,_) = (c,ii)
mkNewECat (c,ii) str = (c ++ str,ii)
------ parser for EBNF grammars
pEBNF :: String -> Err EBNF
pEBNF = parseResultErr (longestOfMany (pJ pERule))
pERule :: Parser Char ERule
pERule = pECat ... pJ (literals ":=" ||| literals "::=") +.. pERHS 0 ..+ jL ";"
pERHS :: Int -> Parser Char ERHS
pERHS 0 = pTList "|" (pERHS 1) *** foldr1 EAlt
pERHS 1 = longestOfMany (pJ (pERHS 2)) *** foldr ESeq EEmpty
pERHS 2 = pERHS 3 ... pJ pUnaryEOp *** (\ (a,f) -> f a)
pERHS 3 = pQuotedString *** ETerm
||| pECat *** ENonTerm ||| pParenth (pERHS 0)
pUnaryEOp :: Parser Char (ERHS -> ERHS)
pUnaryEOp =
lits "*" <<< EStar ||| lits "+" <<< EPlus ||| lits "?" <<< EOpt ||| succeed id
pECat = pIdent *** (\c -> (c,[]))
----------------------------------------------------------------------
-- Module : Parsers
-- some parser combinators a la Wadler and Hutton.
-- (only used in module "EBNF")
-----------------------------------------------------------------------------
infixr 2 |||, +||
infixr 3 ***
infixr 5 .>.
infixr 5 ...
infixr 5 ....
infixr 5 +..
infixr 5 ..+
infixr 6 |>
infixr 3 <<<
type Parser a b = [a] -> [(b,[a])]
parseResults :: Parser a b -> [a] -> [b]
parseResults p s = [x | (x,r) <- p s, null r]
parseResultErr :: Show a => Parser a b -> [a] -> Err b
parseResultErr p s = case parseResults p s of
[x] -> return x
[] -> case
maximumBy (\x y -> compare (length y) (length x)) (s:[r | (_,r) <- p s]) of
r -> Bad $ "\nno parse; reached" ++++ take 300 (show r)
_ -> Bad "ambiguous"
(...) :: Parser a b -> Parser a c -> Parser a (b,c)
(p ... q) s = [((x,y),r) | (x,t) <- p s, (y,r) <- q t]
(.>.) :: Parser a b -> (b -> Parser a c) -> Parser a c
(p .>. f) s = [(c,r) | (x,t) <- p s, (c,r) <- f x t]
(|||) :: Parser a b -> Parser a b -> Parser a b
(p ||| q) s = p s ++ q s
(+||) :: Parser a b -> Parser a b -> Parser a b
p1 +|| p2 = take 1 . (p1 ||| p2)
literal :: (Eq a) => a -> Parser a a
literal x (c:cs) = [(x,cs) | x == c]
literal _ _ = []
(***) :: Parser a b -> (b -> c) -> Parser a c
(p *** f) s = [(f x,r) | (x,r) <- p s]
succeed :: b -> Parser a b
succeed v s = [(v,s)]
fails :: Parser a b
fails s = []
(+..) :: Parser a b -> Parser a c -> Parser a c
p1 +.. p2 = p1 ... p2 *** snd
(..+) :: Parser a b -> Parser a c -> Parser a b
p1 ..+ p2 = p1 ... p2 *** fst
(<<<) :: Parser a b -> c -> Parser a c -- return
p <<< v = p *** (\x -> v)
(|>) :: Parser a b -> (b -> Bool) -> Parser a b
p |> b = p .>. (\x -> if b x then succeed x else fails)
many :: Parser a b -> Parser a [b]
many p = (p ... many p *** uncurry (:)) +|| succeed []
some :: Parser a b -> Parser a [b]
some p = (p ... many p) *** uncurry (:)
longestOfMany :: Parser a b -> Parser a [b]
longestOfMany p = p .>. (\x -> longestOfMany p *** (x:)) +|| succeed []
closure :: (b -> Parser a b) -> (b -> Parser a b)
closure p v = p v .>. closure p ||| succeed v
pJunk :: Parser Char String
pJunk = longestOfMany (satisfy (\x -> elem x "\n\t "))
pJ :: Parser Char a -> Parser Char a
pJ p = pJunk +.. p ..+ pJunk
pTList :: String -> Parser Char a -> Parser Char [a]
pTList t p = p .... many (jL t +.. p) *** (\ (x,y) -> x:y) -- mod. AR 5/1/1999
pTJList :: String -> String -> Parser Char a -> Parser Char [a]
pTJList t1 t2 p = p .... many (literals t1 +.. jL t2 +.. p) *** (uncurry (:))
pElem :: [String] -> Parser Char String
pElem l = foldr (+||) fails (map literals l)
(....) :: Parser Char b -> Parser Char c -> Parser Char (b,c)
p1 .... p2 = p1 ... pJunk +.. p2
item :: Parser a a
item (c:cs) = [(c,cs)]
item [] = []
satisfy :: (a -> Bool) -> Parser a a
satisfy b = item |> b
literals :: (Eq a,Show a) => [a] -> Parser a [a]
literals l = case l of
[] -> succeed []
a:l -> literal a ... literals l *** (\ (x,y) -> x:y)
lits :: (Eq a,Show a) => [a] -> Parser a [a]
lits ts = literals ts
jL :: String -> Parser Char String
jL = pJ . lits
pParenth :: Parser Char a -> Parser Char a
pParenth p = literal '(' +.. pJunk +.. p ..+ pJunk ..+ literal ')'
-- | p,...,p
pCommaList :: Parser Char a -> Parser Char [a]
pCommaList p = pTList "," (pJ p)
-- | the same or nothing
pOptCommaList :: Parser Char a -> Parser Char [a]
pOptCommaList p = pCommaList p ||| succeed []
-- | (p,...,p), poss. empty
pArgList :: Parser Char a -> Parser Char [a]
pArgList p = pParenth (pCommaList p) ||| succeed []
-- | min. 2 args
pArgList2 :: Parser Char a -> Parser Char [a]
pArgList2 p = pParenth (p ... jL "," +.. pCommaList p) *** uncurry (:)
longestOfSome :: Parser a b -> Parser a [b]
longestOfSome p = (p ... longestOfMany p) *** (\ (x,y) -> x:y)
pIdent :: Parser Char String
pIdent = pLetter ... longestOfMany pAlphaPlusChar *** uncurry (:)
where alphaPlusChar c = isAlphaNum c || c=='_' || c=='\''
pLetter, pDigit :: Parser Char Char
pLetter = satisfy (`elem` (['A'..'Z'] ++ ['a'..'z'] ++
['\192' .. '\255'])) -- no such in Char
pDigit = satisfy isDigit
pLetters :: Parser Char String
pLetters = longestOfSome pLetter
pAlphanum, pAlphaPlusChar :: Parser Char Char
pAlphanum = pDigit ||| pLetter
pAlphaPlusChar = pAlphanum ||| satisfy (`elem` "_'")
pQuotedString :: Parser Char String
pQuotedString = literal '"' +.. pEndQuoted where
pEndQuoted =
literal '"' *** (const [])
+|| (literal '\\' +.. item .>. \ c -> pEndQuoted *** (c:))
+|| item .>. \ c -> pEndQuoted *** (c:)
pIntc :: Parser Char Int
pIntc = some (satisfy numb) *** read
where numb x = elem x ['0'..'9']
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