--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Implab/Parsing/Token.cs	Sun Jun 15 19:39:11 2014 +0400
@@ -0,0 +1,67 @@
+using Implab;
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Implab.Parsing {
+    public abstract class Token {
+        public abstract void Accept(IVisitor visitor);
+
+        public Token Extend() {
+            return new CatToken(this, new EndToken());
+        }
+
+        public Token Tag<T>(T tag) where T : IConvertible {
+            return new CatToken(this, new EndToken(tag.ToInt32(CultureInfo.InvariantCulture)));
+        }
+
+        public Token Cat(Token right) {
+            return new CatToken(this, right);
+        }
+
+        public Token Or(Token right) {
+            return new AltToken(this, right);
+        }
+
+        public Token Optional() {
+            return Or(new EmptyToken());
+        }
+
+        public Token EClosure() {
+            return new StarToken(this);
+        }
+
+        public Token Closure() {
+            return new CatToken(this, new StarToken(this));
+        }
+
+        public Token Repeat(int count) {
+            Token token = null;
+
+            for (int i = 0; i < count; i++)
+                token = token != null ? token.Cat(this) : this;
+            return token ?? new EmptyToken();
+        }
+
+        public Token Repeat(int min, int max) {
+            if (min > max || min < 1)
+                throw new ArgumentOutOfRangeException();
+            var token = Repeat(min);
+
+            for (int i = min; i < max; i++)
+                token = token.Cat( this.Optional() );
+            return token;
+        }
+
+        public static Token New<T>(params T[] set) where T : struct, IConvertible {
+            Safe.ArgumentNotNull(set, "set");
+            Token token = null;
+            foreach(var c in set.Distinct())
+                token = token == null ? new SymbolToken(c.ToInt32(CultureInfo.InvariantCulture)) : token.Or(new SymbolToken(c.ToInt32(CultureInfo.InvariantCulture)));
+            return token;
+        }
+    }
+}