[Ironruby-core] Review: fixes for Array#rindex and Array#reverse_each

Daniele Alessandri suppakilla at gmail.com
Sun May 31 07:22:21 EDT 2009


Hi Jim,

I'm a bit late but daytime work got in the way and then I was out of
the country for two weeks :-)
I got rid of the duplicated logic in IListOps.ReverseIndex and
ArrayOps.ReverseEach by implementing a new internal method
(IListOps.ReverseEnumerateIndexes):

http://github.com/nrk/ironruby/commit/76db817d1766b788f995afb02e12c5a72955c77f

As for the specs, I just slightly modified an existing one in a way
that does not affect the test but helped me to discover the bug
(actually this change uses a different condition from the one I used
one month ago as it exposed another bug which got fixed in the above
mentioned commit):

http://github.com/nrk/ironruby/commit/e5497cf87fc479b2bf2ca0b812d979354a86f44c

See also the attached diff.

Thanks,
Daniele


On Thu, Apr 23, 2009 at 22:08, Jim Deville <jdeville at microsoft.com> wrote:
> Can you add specs for rindex that expose the bug you fixed? Also, is there any shared place that you could put the following code:
>         if (self.Count < originalSize) {
>             i = originalSize - i - 1 + self.Count;
>             originalSize = self.Count;
>         }
>
> It would be nice to get rid of the duplicated logic, but I can't think of where it should go.
>
> Other than that, looks good.
> JD
>
>> -----Original Message-----
>> From: ironruby-core-bounces at rubyforge.org [mailto:ironruby-core-
>> bounces at rubyforge.org] On Behalf Of Daniele Alessandri
>> Sent: Thursday, April 23, 2009 12:59 PM
>> To: ironruby-core at rubyforge.org
>> Subject: [Ironruby-core] Review: fixes for Array#rindex and
>> Array#reverse_each
>>
>> Hi,
>> I just pushed two fixes on my repository, the first one addresses a bug
>> in Array#rindex (there was a bug in my last commit) and the second one
>> makes Array#reverse_each compliant with the rubyspecs.
>>
>> http://github.com/nrk/ironruby/commit/d2b18f5d01a49cb62a2ea0c205e1cf123
>> 3ac94e0
>>
>> >From the commit message:
>>
>> * Fixed a bug in IListOps.ReverseIndex (core/array/rindex specs were
>> passing, this bug was triggered under certain conditions different from
>> the ones defined in the specs)
>>
>> * Fixed ArrayOps.ReverseEach to make it not fail when elemens in the
>> array are removed from inside a block.
>>
>> See also the attached diff.
>>
>> Thanks,
>> Daniele
>>
>> --
>> Daniele Alessandri
>> http://www.clorophilla.net/blog/
>> http://twitter.com/JoL1hAHN
> _______________________________________________
> Ironruby-core mailing list
> Ironruby-core at rubyforge.org
> http://rubyforge.org/mailman/listinfo/ironruby-core
>



-- 
Daniele Alessandri
http://www.clorophilla.net/blog/
http://twitter.com/JoL1hAHN
-------------- next part --------------
diff --git a/Merlin/External.LCA_RESTRICTED/Languages/IronRuby/mspec/rubyspec/core/array/rindex_spec.rb b/Merlin/External.LCA_RESTRICTED/Languages/IronRuby/mspec/rubyspec/core/array/rindex_spec.rb
index 4971cf3..6e43c2b 100644
--- a/Merlin/External.LCA_RESTRICTED/Languages/IronRuby/mspec/rubyspec/core/array/rindex_spec.rb
+++ b/Merlin/External.LCA_RESTRICTED/Languages/IronRuby/mspec/rubyspec/core/array/rindex_spec.rb
@@ -17,31 +17,31 @@ describe "Array#rindex" do
 
   it "returns size-1 if last element == to object" do
     [2, 1, 3, 2, 5].rindex(5).should == 4
   end
 
   it "returns 0 if only first element == to object" do
     [2, 1, 3, 1, 5].rindex(2).should == 0
   end
 
   it "returns nil if no element == to object" do
     [1, 1, 3, 2, 1, 3].rindex(4).should == nil
   end
 
   it "does not fail when removing elements from block" do
     sentinel = mock('sentinel')
-    ary = [0, 0, 1, 1, 3, 2, 1, sentinel]
+    ary = [0, 0, 1, 1, 3, 2, 1, sentinel, 4]
 
     sentinel.instance_variable_set(:@ary, ary)
     def sentinel.==(o) @ary.slice!(1..-1); false; end
 
     ary.rindex(0).should == 0
   end
 
   it "properly handles recursive arrays" do
     empty = ArraySpecs.empty_recursive_array
     empty.rindex(empty).should == 0
     empty.rindex(1).should be_nil
 
     array = ArraySpecs.recursive_array
     array.rindex(1).should == 0
     array.rindex([array]).should == 3
diff --git a/Merlin/Main/Languages/Ruby/Libraries.LCA_RESTRICTED/Builtins/ArrayOps.cs b/Merlin/Main/Languages/Ruby/Libraries.LCA_RESTRICTED/Builtins/ArrayOps.cs
index f83c4c7..301007a 100644
--- a/Merlin/Main/Languages/Ruby/Libraries.LCA_RESTRICTED/Builtins/ArrayOps.cs
+++ b/Merlin/Main/Languages/Ruby/Libraries.LCA_RESTRICTED/Builtins/ArrayOps.cs
@@ -546,31 +546,27 @@ namespace IronRuby.Builtins {
         [RubyMethod("reverse!")]
         public static RubyArray/*!*/ InPlaceReverse(RubyContext/*!*/ context, RubyArray/*!*/ self) {
             RubyUtils.RequiresNotFrozen(context, self);
             self.Reverse();
             return self;
         }
 
         [RubyMethod("reverse_each")]
         public static object ReverseEach(RubyContext/*!*/ context, BlockParam block, RubyArray/*!*/ self) {
             Assert.NotNull(context, self);
 
             if (self.Count > 0 && block == null) {
                 throw RubyExceptions.NoBlockGiven();
             }
 
-            for (int originalSize = self.Count, i = originalSize - 1; i >= 0; i--) {
+            foreach (int index in IListOps.ReverseEnumerateIndexes(self)) {
                 object result;
-                if (block.Yield(self[i], out result)) {
+                if (block.Yield(self[index], out result)) {
                     return result;
                 }
-                if (self.Count < originalSize) {
-                    i = originalSize - i - 1 + self.Count;
-                    originalSize = self.Count;
-                }
             }
             return self;
         }
 
         #endregion
     }
 }
diff --git a/Merlin/Main/Languages/Ruby/Libraries.LCA_RESTRICTED/Extensions/IListOps.cs b/Merlin/Main/Languages/Ruby/Libraries.LCA_RESTRICTED/Extensions/IListOps.cs
index e1197ad..3224c55 100644
--- a/Merlin/Main/Languages/Ruby/Libraries.LCA_RESTRICTED/Extensions/IListOps.cs
+++ b/Merlin/Main/Languages/Ruby/Libraries.LCA_RESTRICTED/Extensions/IListOps.cs
@@ -138,30 +138,40 @@ namespace IronRuby.Builtins {
             if (array != null) {
                 return array.CreateInstance();
             }
             
             // interop - call a default ctor to get an instance:
             var allocate = allocateStorage.GetCallSite("allocate", 0);
             var cls = allocateStorage.Context.GetClassOf(list);
             var result = allocate.Target(allocate, cls) as IList;
             if (result != null) {
                 return result;
             }
 
             throw RubyExceptions.CreateTypeError(String.Format("{0}#allocate should return IList", cls.Name));
         }
 
+        internal static IEnumerable<Int32>/*!*/ ReverseEnumerateIndexes(IList/*!*/ collection) {
+            for (int originalSize = collection.Count, i = originalSize - 1; i >= 0; i--) {
+                yield return i;
+                if (collection.Count < originalSize) {
+                    i = originalSize - (originalSize - collection.Count);
+                    originalSize = collection.Count;
+                }
+            }
+        }
+
         #endregion
 
         #region initialize_copy, replace, clear, to_a, to_ary
 
         [RubyMethod("replace")]
         [RubyMethod("initialize_copy", RubyMethodAttributes.PrivateInstance)]
         public static IList/*!*/ Replace(RubyContext/*!*/ context, IList/*!*/ self, [NotNull, DefaultProtocol]IList/*!*/ other) {
             RubyUtils.RequiresNotFrozen(context, self);
 
             self.Clear();
             AddRange(self, other);
             return self;
         }
 
         [RubyMethod("clear")]
@@ -1022,37 +1032,33 @@ namespace IronRuby.Builtins {
             return Index(equals, self, item) != null;
         }
 
         [RubyMethod("index")]
         public static object Index(BinaryOpStorage/*!*/ equals, IList/*!*/ self, object item) {
             for (int i = 0; i < self.Count; ++i) {
                 if (Protocols.IsEqual(equals, self[i], item)) {
                     return i;
                 }
             }
             return null;
         }
 
         [RubyMethod("rindex")]
         public static object ReverseIndex(BinaryOpStorage/*!*/ equals, IList/*!*/ self, object item) {
-            for (int originalSize = self.Count, i = originalSize - 1; i >= 0; i--) {
-                if (Protocols.IsEqual(equals, self[i], item)) {
-                    return i;
-                }
-                if (self.Count < originalSize) {
-                    i = originalSize - i - 1 + self.Count;
-                    originalSize = self.Count;
+            foreach (int index in IListOps.ReverseEnumerateIndexes(self)) {
+                if (Protocols.IsEqual(equals, self[index], item)) {
+                    return index;
                 }
             }
             return null;
         }
 
         #endregion
 
         #region indexes, indices, values_at
 
         [RubyMethod("indexes")]
         [RubyMethod("indices")]
         public static object Indexes(ConversionStorage<int>/*!*/ fixnumCast, 
             CallSiteStorage<Func<CallSite, RubyClass, object>>/*!*/ allocateStorage,
             IList/*!*/ self, [NotNull]params object[]/*!*/ values) {
             fixnumCast.Context.ReportWarning("Array#indexes and Array#indices are deprecated; use Array#values_at");


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