--- a/Implab/Automaton/RegularExpressions/Grammar.cs	Thu Mar 10 01:19:33 2016 +0300
+++ b/Implab/Automaton/RegularExpressions/Grammar.cs	Mon Mar 14 01:19:38 2016 +0300
@@ -66,23 +66,21 @@
             return Token<TTag>.New( Enumerable.Range(0, AlphabetBuilder.Count).Except(TranslateOrDie(symbols)).ToArray() );
         }
 
-        protected void BuildDFA(Token<TTag> lang, IDFATableBuilder<TTag> dfaTable, IAlphabetBuilder<TSymbol> dfaAlphabet) {
-            Safe.ArgumentNotNull(lang, "lang");
-            Safe.ArgumentNotNull(dfaAlphabet, "dfaAlphabet");
-
-            var dfa = new RegularDFADefinition<TSymbol, TTag>(AlphabetBuilder);
+        protected abstract IAlphabetBuilder<TSymbol> CreateAlphabet();
 
-            var builder = new RegularDFABuilder<TTag>();
+        protected RegularDFA<TSymbol, TTag> BuildDFA(Token<TTag> regexp) {
+            
+            var dfa = new RegularDFA<TSymbol, TTag>(AlphabetBuilder);
 
-            lang.Accept( builder );
+            var visitor = new RegularExpressionVisitor<TTag>();
+            regexp.Accept( visitor );
 
-            builder.BuildDFA(dfa);
+            visitor.BuildDFA(dfa);
 
             if (dfa.IsFinalState(dfa.InitialState))
                 throw new ApplicationException("The specified language contains empty token");
 
-            dfa.Optimize(dfaTable, dfaAlphabet);
-
+            return dfa.Optimize(CreateAlphabet());
         }
 
     }