From 99af757b0603b2b8ea904edc011aac53cf6a26b3 Mon Sep 17 00:00:00 2001
From: bringert <bringert@cs.chalmers.se>
Date: Sat, 24 Mar 2007 17:30:04 +0000
Subject: [PATCH] Modified the LC_LR implementation to only produce rules using
 A-X categories when those categories have any productions.

---
 src/GF/Speech/TransformCFG.hs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/GF/Speech/TransformCFG.hs b/src/GF/Speech/TransformCFG.hs
index 232239b20..dcb666bf3 100644
--- a/src/GF/Speech/TransformCFG.hs
+++ b/src/GF/Speech/TransformCFG.hs
@@ -125,6 +125,7 @@ removeLeftRecursion start gr
                x <- properLeftCornersOf a,
                not (isLeftRecursive x),
                let a_x = mkCat (Cat a) x,
+               a_x `Set.member` newCats,
                let n' = symbol (\_ -> CFApp (CFRes 1) (CFRes 0))
                                (\_ -> CFRes 0) x] 
     scheme2 = [CFRule a_x (beta++[Cat a_b]) n' | 
@@ -147,6 +148,8 @@ removeLeftRecursion start gr
                                (\_ -> n) x]
     scheme4 = catSetRules gr $ Set.fromList $ filter (not . isLeftRecursive . Cat) cats
 
+    newCats = Set.fromList (map lhsCat (scheme2 ++ scheme3))
+
     shiftTerm :: CFTerm -> CFTerm
     shiftTerm (CFObj f ts) = CFObj f (map shiftTerm ts)
     shiftTerm (CFRes 0) = CFVar 1