Index: Integer.cs
===================================================================
--- Integer.cs	(revision 71)
+++ Integer.cs	(working copy)
@@ -41,20 +41,68 @@
 
         //ceil
         //chr
-        //downto
         //floor
         //integer?
-        //next
         //round
-        //succ
 
         [RubyMethod("succ")]
         public static int Succ(int/*!*/ instance) {
             return ((int)instance) + 1;
         }
 
+        [RubyMethod("next")]
+        public static int Next(int/*!*/ instance) {
+            return Succ(instance);
+        }
+
+        private static DynamicSite<BlockParam, int, object> UpToSharedSite = RuntimeHelpers.CreateSimpleCallSite<BlockParam, int, object>();
+
+        [RubyMethod("upto")]
+        public static object UpTo(CodeContext/*!*/ context, int self, BlockParam block, int limit) {
+            Contract.RequiresNotNull(context, "context");
+
+            if (self < limit && block == null) {
+                throw RubyExceptions.CreateLocalJumpError("no block given");
+            }
+
+            for (int i = self; i <= limit; i++) {
+                object result = UpToSharedSite.Invoke(context, block, i);
+                if (block.BlockJumped(result)) return result;
+            }
+
+            return self;
+        }
+
+        [RubyMethod("upto")]
+        public static object UpTo(CodeContext/*!*/ context, BigInteger/*!*/ self, BlockParam block) {
+            throw new NotImplementedException();
+        }
+
+        private static DynamicSite<BlockParam, int, object> DownToSharedSite = RuntimeHelpers.CreateSimpleCallSite<BlockParam, int, object>();
+
+        [RubyMethod("downto")]
+        public static object DownTo(CodeContext/*!*/ context, int self, BlockParam block, int limit) {
+            Contract.RequiresNotNull(context, "context");
+
+            if (self > limit && block == null) {
+                throw RubyExceptions.CreateLocalJumpError("no block given");
+            }
+
+            for (int i = self; i >= limit; i--) {
+                object result = DownToSharedSite.Invoke(context, block, i);
+                if (block.BlockJumped(result)) return result;
+            }
+
+            return self;
+        }
+
+        [RubyMethod("downto")]
+        public static object DownTo(CodeContext/*!*/ context, BigInteger/*!*/ self, BlockParam block) {
+            throw new NotImplementedException();
+        }
+
         private static DynamicSite<BlockParam, int, object> TimesSharedSite = RuntimeHelpers.CreateSimpleCallSite<BlockParam, int, object>();
- 
+
         [RubyMethod("times")]
         public static object Times(CodeContext/*!*/ context, int self, BlockParam block) {
             Contract.RequiresNotNull(context, "context");
@@ -63,11 +111,9 @@
                 throw RubyExceptions.CreateLocalJumpError("no block given");
             }
 
-            int i = 0;
-            while (i < self) {
+            for (int i = 0; i < self; i++) {
                 object result = TimesSharedSite.Invoke(context, block, i);
                 if (block.BlockJumped(result)) return result;
-                i++;
             }
 
             return self;