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authorpeb <unknown>2005-04-14 17:38:36 +0000
committerpeb <unknown>2005-04-14 17:38:36 +0000
commit5207c27bffd077f1ab322824b485fc6c92d554eb (patch)
treef8a54bde5d80925f5590755859ad31c2e6f9ac3d /src/GF/Speech/TransformCFG.hs
parentf070a412a1256b39e60b3a819e18c61922a7fe79 (diff)
"Committed_by_peb"
Diffstat (limited to 'src/GF/Speech/TransformCFG.hs')
-rw-r--r--src/GF/Speech/TransformCFG.hs58
1 files changed, 33 insertions, 25 deletions
diff --git a/src/GF/Speech/TransformCFG.hs b/src/GF/Speech/TransformCFG.hs
index 8dd81cb91..6a1b7c817 100644
--- a/src/GF/Speech/TransformCFG.hs
+++ b/src/GF/Speech/TransformCFG.hs
@@ -5,22 +5,28 @@
-- Stability : (stable)
-- Portability : (portable)
--
--- > CVS $Date: 2005/04/11 13:53:39 $
+-- > CVS $Date: 2005/04/14 18:38:36 $
-- > CVS $Author: peb $
--- > CVS $Revision: 1.9 $
+-- > CVS $Revision: 1.10 $
--
-- This module does some useful transformations on CFGs.
--
-- FIXME: remove cycles
+--
+-- peb thinks: most of this module should be moved to GF.Conversion...
-----------------------------------------------------------------------------
module TransformCFG (makeNice, CFRule_) where
import Ident
-import GF.OldParsing.CFGrammar
-import GF.OldParsing.Utilities (Symbol(..))
-import GF.OldParsing.GrammarTypes
-import GF.Printing.PrintParser
+-- import GF.OldParsing.CFGrammar
+-- import GF.OldParsing.Utilities (Symbol(..))
+-- import GF.OldParsing.GrammarTypes
+-- import GF.Printing.PrintParser
+import GF.Formalism.CFG
+import GF.Formalism.Utilities (Symbol(..), mapSymbol)
+import GF.Conversion.Types
+import GF.Infra.Print
import Data.FiniteMap
import Data.List
@@ -30,63 +36,65 @@ import Debug.Trace
-- | not very nice to get replace the structured CFCat type with a simple string
-type CFRule_ = Rule CFName String Tokn
+type CFRule_ = CFRule Cat_ Name Token
+type Cat_ = String
-type CFRules = FiniteMap String [CFRule_]
+type CFRules = FiniteMap Cat_ [CFRule_]
-makeNice :: CFGrammar -> [CFRule_]
+makeNice :: CGrammar -> [CFRule_]
makeNice = concat . eltsFM . makeNice' . groupProds . cfgToCFRules
where makeNice' = removeLeftRecursion . removeEmptyCats
-cfgToCFRules :: CFGrammar -> [CFRule_]
-cfgToCFRules cfg = [Rule (catToString c) (map symb r) n | Rule c r n <- cfg]
- where symb (Cat c) = Cat (catToString c)
- symb (Tok t) = Tok t
+cfgToCFRules :: CGrammar -> [CFRule_]
+cfgToCFRules cfg = [CFRule (catToString c) (map symb r) n | CFRule c r n <- cfg]
+ where symb = mapSymbol catToString id
+ -- symb (Cat c) = Cat (catToString c)
+ -- symb (Tok t) = Tok t
catToString = prt
-- | Group productions by their lhs categories
groupProds :: [CFRule_] -> CFRules
groupProds = addListToFM_C (++) emptyFM . map (\rs -> (ruleCat rs,[rs]))
- where ruleCat (Rule c _ _) = c
+ where ruleCat (CFRule c _ _) = c
-- | Remove productions which use categories which have no productions
removeEmptyCats :: CFRules -> CFRules
removeEmptyCats rss = listToFM $ fix removeEmptyCats' $ fmToList rss
where
- removeEmptyCats' :: [(String,[CFRule_])] -> [(String,[CFRule_])]
+ removeEmptyCats' :: [(Cat_,[CFRule_])] -> [(Cat_,[CFRule_])]
removeEmptyCats' rs = k'
where
keep = filter (not . null . snd) rs
- allCats = nub [c | (_,r) <- rs, Rule _ rhs _ <- r, Cat c <- rhs]
+ allCats = nub [c | (_,r) <- rs, CFRule _ rhs _ <- r, Cat c <- rhs]
emptyCats = filter (nothingOrNull . flip lookup rs) allCats
k' = map (\ (c,xs) -> (c, filter (not . anyUsedBy emptyCats) xs)) keep
-anyUsedBy :: [String] -> CFRule_ -> Bool
-anyUsedBy ss (Rule _ r _) = or [c `elem` ss | Cat c <- r]
+anyUsedBy :: [Cat_] -> CFRule_ -> Bool
+anyUsedBy ss (CFRule _ r _) = or [c `elem` ss | Cat c <- r]
removeLeftRecursion :: CFRules -> CFRules
removeLeftRecursion rs = listToFM $ concatMap removeDirectLeftRecursion $ map handleProds $ fmToList rs
where
handleProds (c, r) = (c, concatMap handleProd r)
- handleProd (Rule ai (Cat aj:alpha) n) | aj < ai =
+ handleProd (CFRule ai (Cat aj:alpha) n) | aj < ai =
-- FIXME: this will give multiple rules with the same name
- [Rule ai (beta ++ alpha) n | Rule _ beta _ <- fromJust (lookupFM rs aj)]
+ [CFRule ai (beta ++ alpha) n | CFRule _ beta _ <- fromJust (lookupFM rs aj)]
handleProd r = [r]
-removeDirectLeftRecursion :: (String,[CFRule_]) -- ^ All productions for a category
- -> [(String,[CFRule_])]
+removeDirectLeftRecursion :: (Cat_,[CFRule_]) -- ^ All productions for a category
+ -> [(Cat_,[CFRule_])]
removeDirectLeftRecursion (a,rs) | null dr = [(a,rs)]
| otherwise = [(a, as), (a', a's)]
where
a' = a ++ "'" -- FIXME: this might not be unique
(dr,nr) = partition isDirectLeftRecursive rs
as = maybeEndWithA' nr
- is = [Rule a' (tail r) n | Rule _ r n <- dr]
+ is = [CFRule a' (tail r) n | CFRule _ r n <- dr]
a's = maybeEndWithA' is
- maybeEndWithA' xs = xs ++ [Rule c (r++[Cat a']) n | Rule c r n <- xs]
+ maybeEndWithA' xs = xs ++ [CFRule c (r++[Cat a']) n | CFRule c r n <- xs]
isDirectLeftRecursive :: CFRule_ -> Bool
-isDirectLeftRecursive (Rule c (Cat c':_) _) = c == c'
+isDirectLeftRecursive (CFRule c (Cat c':_) _) = c == c'
isDirectLeftRecursive _ = False