Files
gf-core/src/GF/Speech/SRG.hs

87 lines
2.7 KiB
Haskell

----------------------------------------------------------------------
-- |
-- Module : SRG
-- Maintainer : BB
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/10/26 17:14:03 $
-- > CVS $Author: bringert $
-- > CVS $Revision: 1.19 $
--
-- 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
--
-- FIXME: figure out name prefix from grammar name
-----------------------------------------------------------------------------
module GF.Speech.SRG where
import GF.Data.Utilities
import GF.Infra.Ident
import GF.Formalism.CFG
import GF.Formalism.Utilities (Symbol(..))
import GF.Conversion.Types
import GF.Infra.Print
import GF.Speech.TransformCFG
import GF.Infra.Option
import Data.List
import Data.Maybe (fromMaybe)
import Data.FiniteMap
data SRG = SRG { grammarName :: String -- ^ grammar name
, startCat :: String -- ^ start category name
, origStartCat :: String -- ^ original start category name
, rules :: [SRGRule]
}
data SRGRule = SRGRule String String [SRGAlt] -- ^ SRG category name, original category name
-- and productions
type SRGAlt = [Symbol String Token]
-- | SRG category name and original name
type CatName = (String,String)
type CatNames = FiniteMap String String
makeSRG :: Ident -- ^ Grammar name
-> Options -- ^ Grammar options
-> CGrammar -- ^ A context-free grammar
-> SRG
makeSRG i opts gr = SRG { grammarName = name,
startCat = lookupFM_ names origStart,
origStartCat = origStart,
rules = map (cfgRulesToSRGRule names) cfgRules }
where
name = prIdent i
origStart = getStartCat opts
gr' = removeLeftRecursion $ removeIdenticalRules $ removeEmptyCats $ cfgToCFRules gr
(cats,cfgRules) = unzip gr'
names = mkCatNames name cats
cfgRulesToSRGRule :: FiniteMap String String -> [CFRule_] -> SRGRule
cfgRulesToSRGRule names rs@(r:_) = SRGRule cat origCat rhs
where origCat = lhsCat r
cat = lookupFM_ names origCat
rhs = nub $ map (map renameCat . ruleRhs) rs
renameCat (Cat c) = Cat (lookupFM_ names c)
renameCat t = t
mkCatNames :: String -- ^ Category name prefix
-> [String] -- ^ Original category names
-> FiniteMap String String -- ^ Maps original names to SRG names
mkCatNames prefix origNames = listToFM (zip origNames names)
where names = [prefix ++ "_" ++ show x | x <- [0..]]
--
-- * Utilities for building and printing SRGs
--
lookupFM_ :: (Ord key, Show key) => FiniteMap key elt -> key -> elt
lookupFM_ fm k = lookupWithDefaultFM fm (error $ "Key not found: " ++ show k) k
prtS :: Print a => a -> ShowS
prtS = showString . prt