richer extraction syntax

lib/resource/exper/english/AdverbEng.gf

@@ -0,0 +1,21 @@
+concrete AdverbEng of Adverb = CatEng ** open ResEng, Prelude in {
+
+  lin
+    PositAdvAdj a = {s = a.s ! AAdv} ;
+    ComparAdvAdj cadv a np = {
+      s = cadv.s ++ a.s ! AAdv ++ "than" ++ np.s ! Nom
+      } ;
+    ComparAdvAdjS cadv a s = {
+      s = cadv.s ++ a.s ! AAdv ++ "than" ++ s.s
+      } ;
+
+    PrepNP prep np = {s = prep.s ++ np.s ! Acc} ;
+
+    AdAdv = cc2 ;
+
+    SubjS = cc2 ;
+    AdvSC s = s ; --- this rule give stack overflow in ordinary parsing
+
+    AdnCAdv cadv = {s = cadv.s ++ "than"} ;
+
+}