--- a/Implab/Parsing/CDFADefinition.cs	Thu Feb 18 11:03:47 2016 +0300
+++ b/Implab/Parsing/CDFADefinition.cs	Thu Feb 18 14:34:02 2016 +0300
@@ -1,29 +1,17 @@
-using Implab;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
+namespace Implab.Parsing {
+    public class CDFADefinition : DFADefinition {
+        readonly CharAlphabet m_alphabet;
 
-namespace Implab.Parsing {
-    public class CDFADefinition : DFADefinitionBase {
-        readonly Alphabet m_alphabet;
-
-        public Alphabet Alphabet {
+        public CharAlphabet Alphabet {
             get { return m_alphabet; }
         }
 
-        public override int AlphabetSize {
-            get { return m_alphabet.Count; }
-        }
-
-        public CDFADefinition(Alphabet alphabet): base() {
-            Safe.ArgumentNotNull(alphabet, "alphabet");
+        public CDFADefinition(CharAlphabet alphabet): base(alphabet.Count) {
             m_alphabet = alphabet;
         }
 
         public CDFADefinition Optimize() {
-            var optimized = new CDFADefinition(new Alphabet());
+            var optimized = new CDFADefinition(new CharAlphabet());
 
             Optimize(optimized, m_alphabet, optimized.Alphabet);
             return optimized;