Added --output-format=nolr. Minor makeRegular refactoring.

src/GF/Compile/Export.hs

@@ -37,6 +37,7 @@ exportPGF opts fmt pgf =
       FmtProlog       -> multi "pl"  grammar2prolog 
       FmtProlog_Abs   -> multi "pl"  grammar2prolog_abs 
       FmtBNF          -> single "bnf"   bnfPrinter
+      FmtNoLR         -> single "bnf"   nonLeftRecursivePrinter
       FmtRegular      -> single "bnf"   regularPrinter
       FmtFCFG         -> single "fcfg"  fcfgPrinter
       FmtSRGS_XML     -> single "grxml" (srgsXmlPrinter sisr)

src/GF/Infra/Option.hs

@@ -88,6 +88,7 @@ data OutputFormat = FmtPGF
                   | FmtProlog_Abs
                   | FmtBNF
                   | FmtRegular
+                  | FmtNoLR
                   | FmtFCFG
                   | FmtSRGS_XML
                   | FmtSRGS_XML_NonRec
@@ -458,6 +459,7 @@ outputFormats =
      ("prolog_abs",   FmtProlog_Abs),
      ("bnf",          FmtBNF),
      ("regular",      FmtRegular),
+     ("nolr",         FmtNoLR),
      ("fcfg",         FmtFCFG),
      ("srgs_xml",     FmtSRGS_XML),
      ("srgs_xml_nonrec",     FmtSRGS_XML_NonRec),

src/GF/Speech/CFG.hs

@@ -190,14 +190,13 @@ makeSimpleRegular = makeRegular . topDownFilter . bottomUpFilter . removeCycles
 
 -- Use the transformation algorithm from \"Regular Approximation of Context-free
 -- Grammars through Approximation\", Mohri and Nederhof, 2000
--- to create an over-generating regular frammar for a context-free 
+-- to create an over-generating regular grammar for a context-free 
 -- grammar
 makeRegular :: CFG -> CFG
 makeRegular g = g { cfgRules = groupProds $ concatMap trSet (mutRecCats True g) }
   where trSet cs | allXLinear cs rs = rs
-                 | otherwise = concatMap handleCat csl
-            where csl = Set.toList cs 
-                  rs = catSetRules g cs
+                 | otherwise = concatMap handleCat (Set.toList cs)
+            where rs = catSetRules g cs
                   handleCat c = [CFRule c' [] (mkCFTerm (c++"-empty"))] -- introduce A' -> e
                                 ++ concatMap (makeRightLinearRules c) (catRules g c)
                       where c' = newCat c

src/GF/Speech/PGFToCFG.hs

@@ -4,7 +4,8 @@
 --
 -- Approximates PGF grammars with context-free grammars.
 ----------------------------------------------------------------------
-module GF.Speech.PGFToCFG (bnfPrinter, regularPrinter, fcfgPrinter, pgfToCFG) where
+module GF.Speech.PGFToCFG (bnfPrinter, nonLeftRecursivePrinter, regularPrinter, 
+                           fcfgPrinter, pgfToCFG) where
 
 import PGF.CId
 import PGF.Data as PGF
@@ -21,10 +22,16 @@ import Data.Set (Set)
 import qualified Data.Set as Set
 
 bnfPrinter :: PGF -> CId -> String
-bnfPrinter pgf cnc = prCFG $ pgfToCFG pgf cnc
+bnfPrinter = toBNF id
+
+nonLeftRecursivePrinter :: PGF -> CId -> String
+nonLeftRecursivePrinter = toBNF removeLeftRecursion
 
 regularPrinter :: PGF -> CId -> String
-regularPrinter pgf cnc = prCFG $ makeSimpleRegular $ pgfToCFG pgf cnc
+regularPrinter = toBNF makeRegular
+
+toBNF :: (CFG -> CFG) -> PGF -> CId -> String
+toBNF f pgf cnc = prCFG $ f $ pgfToCFG pgf cnc
 
 -- FIXME: move this somewhere else
 fcfgPrinter :: PGF -> CId -> String