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|
----------------------------------------------------------------------
-- |
-- Module : SRG
--
-- Representation of, conversion to, and utilities for
-- printing of a general Speech Recognition Grammar.
--
-- FIXME: remove \/ warn \/ fail if there are int \/ string literal
-- categories in the grammar
----------------------------------------------------------------------
module GF.Speech.SRG (SRG(..), SRGRule(..), SRGAlt(..), SRGItem, SRGSymbol
, SRGNT, CFTerm
, ebnfPrinter
, makeNonLeftRecursiveSRG
, makeNonRecursiveSRG
, isExternalCat
, lookupFM_
) where
--import GF.Data.Operations
import GF.Data.Utilities
--import GF.Infra.Ident
import GF.Infra.Option
import GF.Grammar.CFG
import GF.Speech.PGFToCFG
--import GF.Data.Relation
--import GF.Speech.FiniteState
import GF.Speech.RegExp
import GF.Speech.CFGToFA
--import GF.Infra.Option
import PGF
import Data.List
--import Data.Maybe (fromMaybe, maybeToList)
import Data.Map (Map)
import qualified Data.Map as Map
import Data.Set (Set)
import qualified Data.Set as Set
--import Debug.Trace
data SRG = SRG { srgName :: String -- ^ grammar name
, srgStartCat :: Cat -- ^ start category name
, srgExternalCats :: Set Cat
, srgLanguage :: Maybe String -- ^ The language for which the grammar
-- is intended, e.g. en-UK
, srgRules :: [SRGRule]
}
deriving (Eq,Show)
data SRGRule = SRGRule Cat [SRGAlt]
deriving (Eq,Show)
-- | maybe a probability, a rule name and an EBNF right-hand side
data SRGAlt = SRGAlt (Maybe Double) CFTerm SRGItem
deriving (Eq,Show)
type SRGItem = RE SRGSymbol
type SRGSymbol = Symbol SRGNT Token
-- | An SRG non-terminal. Category name and its number in the profile.
type SRGNT = (Cat, Int)
ebnfPrinter :: Options -> PGF -> CId -> String
ebnfPrinter opts pgf cnc = prSRG opts $ makeSRG opts pgf cnc
-- | Create a compact filtered non-left-recursive SRG.
makeNonLeftRecursiveSRG :: Options -> PGF -> CId -> SRG
makeNonLeftRecursiveSRG opts = makeSRG opts'
where
opts' = setDefaultCFGTransform opts CFGNoLR True
makeSRG :: Options -> PGF -> CId -> SRG
makeSRG opts = mkSRG cfgToSRG preprocess
where
cfgToSRG cfg = [cfRulesToSRGRule rs | (_,rs) <- allRulesGrouped cfg]
preprocess = maybeTransform opts CFGMergeIdentical mergeIdentical
. maybeTransform opts CFGNoLR removeLeftRecursion
. maybeTransform opts CFGRegular makeRegular
. maybeTransform opts CFGTopDownFilter topDownFilter
. maybeTransform opts CFGBottomUpFilter bottomUpFilter
. maybeTransform opts CFGRemoveCycles removeCycles
. maybeTransform opts CFGStartCatOnly purgeExternalCats
setDefaultCFGTransform :: Options -> CFGTransform -> Bool -> Options
setDefaultCFGTransform opts t b = setCFGTransform t b `addOptions` opts
maybeTransform :: Options -> CFGTransform -> (CFG -> CFG) -> (CFG -> CFG)
maybeTransform opts t f = if cfgTransform opts t then f else id
{-
traceStats s g = trace ("---- " ++ s ++ ": " ++ stats g {- ++ "\n" ++ prCFRules g ++ "----" -}) g
stats g = "Categories: " ++ show (countCats g)
++ ", External categories: " ++ show (Set.size (cfgExternalCats g))
++ ", Rules: " ++ show (countRules g)
-}
makeNonRecursiveSRG :: Options
-> PGF
-> CId -- ^ Concrete syntax name.
-> SRG
makeNonRecursiveSRG opts = mkSRG cfgToSRG id
where
cfgToSRG cfg = [SRGRule l [SRGAlt Nothing dummyCFTerm (dfaToSRGItem dfa)] | (l,dfa) <- dfas]
where
MFA _ dfas = cfgToMFA cfg
dfaToSRGItem = mapRE dummySRGNT . minimizeRE . dfa2re
dummyCFTerm = CFMeta (mkCId "dummy")
dummySRGNT = mapSymbol (\c -> (c,0)) id
mkSRG :: (CFG -> [SRGRule]) -> (CFG -> CFG) -> PGF -> CId -> SRG
mkSRG mkRules preprocess pgf cnc =
SRG { srgName = showCId cnc,
srgStartCat = cfgStartCat cfg,
srgExternalCats = cfgExternalCats cfg,
srgLanguage = languageCode pgf cnc,
srgRules = mkRules cfg }
where cfg = renameCats (showCId cnc) $ preprocess $ pgfToCFG pgf cnc
-- | Renames all external cats C to C_cat, and all internal cats C_X (where X is any string),
-- to C_N where N is an integer.
renameCats :: String -> CFG -> CFG
renameCats prefix cfg = mapCFGCats renameCat cfg
where renameCat c | isExternal c = c ++ "_cat"
| otherwise = Map.findWithDefault (badCat c) c names
isExternal c = c `Set.member` cfgExternalCats cfg
catsByPrefix = buildMultiMap [(takeWhile (/='_') cat, cat) | cat <- allCats' cfg, not (isExternal cat)]
names = Map.fromList [(c,pref++"_"++show i) | (pref,cs) <- catsByPrefix, (c,i) <- zip cs [1..]]
badCat c = error ("GF.Speech.SRG.renameCats: " ++ c ++ "\n" ++ prCFG cfg)
cfRulesToSRGRule :: [CFRule] -> SRGRule
cfRulesToSRGRule rs@(r:_) = SRGRule (ruleLhs r) rhs
where
alts = [((n,Nothing),mkSRGSymbols 0 ss) | Rule c ss n <- rs]
rhs = [SRGAlt p n (srgItem sss) | ((n,p),sss) <- buildMultiMap alts ]
mkSRGSymbols _ [] = []
mkSRGSymbols i (NonTerminal c:ss) = NonTerminal (c,i) : mkSRGSymbols (i+1) ss
mkSRGSymbols i (Terminal t:ss) = Terminal t : mkSRGSymbols i ss
srgLHSCat :: SRGRule -> Cat
srgLHSCat (SRGRule c _) = c
isExternalCat :: SRG -> Cat -> Bool
isExternalCat srg c = c `Set.member` srgExternalCats srg
--
-- * Size-optimized EBNF SRGs
--
srgItem :: [[SRGSymbol]] -> SRGItem
srgItem = unionRE . map mergeItems . sortGroupBy (compareBy filterCats)
-- non-optimizing version:
--srgItem = unionRE . map seqRE
-- | Merges a list of right-hand sides which all have the same
-- sequence of non-terminals.
mergeItems :: [[SRGSymbol]] -> SRGItem
mergeItems = minimizeRE . ungroupTokens . minimizeRE . unionRE . map seqRE . map groupTokens
groupTokens :: [SRGSymbol] -> [Symbol SRGNT [Token]]
groupTokens [] = []
groupTokens (Terminal t:ss) = case groupTokens ss of
Terminal ts:ss' -> Terminal (t:ts):ss'
ss' -> Terminal [t]:ss'
groupTokens (NonTerminal c:ss) = NonTerminal c : groupTokens ss
ungroupTokens :: RE (Symbol SRGNT [Token]) -> RE SRGSymbol
ungroupTokens = joinRE . mapRE (symbol (RESymbol . NonTerminal) (REConcat . map (RESymbol . Terminal)))
--
-- * Utilities for building and printing SRGs
--
prSRG :: Options -> SRG -> String
prSRG opts srg = prProductions $ map prRule $ ext ++ int
where
sisr = flag optSISR opts
(ext,int) = partition (isExternalCat srg . srgLHSCat) (srgRules srg)
prRule (SRGRule c alts) = (c,unwords (intersperse "|" (concatMap prAlt alts)))
prAlt (SRGAlt _ t rhs) =
-- FIXME: hack: we high-jack the --sisr flag to add
-- a simple lambda calculus format for semantic interpretation
-- Maybe the --sisr flag should be renamed.
case sisr of
Just _ ->
-- copy tags to each part of a top-level union,
-- to get simpler output
case rhs of
REUnion xs -> map prOneAlt xs
_ -> [prOneAlt rhs]
where prOneAlt a = prRE prSym a ++ " { " ++ prCFTerm t ++ " }"
Nothing -> [prRE prSym rhs]
prSym = symbol fst (\t -> "\""++ t ++"\"")
lookupFM_ :: (Ord key, Show key) => Map key elt -> key -> elt
lookupFM_ fm k = Map.findWithDefault err k fm
where err = error $ "Key not found: " ++ show k
++ "\namong " ++ show (Map.keys fm)
|
