remove unnecessary rule.

kartikeya-tammuz · kartikeya-tammuz · commit 21fd97303965 · 2017-06-11T14:46:13.000+08:00
diff --git a/chapter-7/exercises.pl b/chapter-7/exercises.pl
@@ -96,7 +96,6 @@
 
 %% nonterminals
 s --> [].
-s --> l,r,r.
 s --> l,s,r,r.
 
 %% terminals
