[Fixes #137] Improve reporting

1 files changed, 18 insertions, 16 deletions

diff --git a/lib/racc/grammar.rb b/lib/racc/grammar.rb
index fa81534338..3444dfcce3 100644
--- a/lib/racc/grammar.rb
+++ b/lib/racc/grammar.rb
@@ -86,14 +86,15 @@ module Racc
     end
 
     def n_useless_nonterminals
-      @n_useless_nonterminals ||=
-          begin
-            n = 0
-            @symboltable.each_nonterminal do |sym|
-              n += 1 if sym.useless?
-            end
-            n
-          end
+      @n_useless_nonterminals ||= each_useless_nonterminal.count
+    end
+
+    def each_useless_nonterminal
+      return to_enum __method__ unless block_given?
+
+      @symboltable.each_nonterminal do |sym|
+        yield sym if sym.useless?
+      end
     end
 
     def useless_rule_exist?
@@ -101,14 +102,15 @@ module Racc
     end
 
     def n_useless_rules
-      @n_useless_rules ||=
-          begin
-            n = 0
-            each do |r|
-              n += 1 if r.useless?
-            end
-            n
-          end
+      @n_useless_rules ||= each_useless_rule.count
+    end
+
+    def each_useless_rule
+      return to_enum __method__ unless block_given?
+
+      each do |r|
+        yield r if r.useless?
+      end
     end
 
     def nfa