great to hear, and already looking forward to the next release :) just wondering though, you mentioned that it's possible to provide your own implementation of !=. how would one do that? if i try to define a != method, i get an 'unexpected !=' error
On Fri, Sep 10, 2010 at 7:09 AM, Tomas Matousek < tomas.matou...@microsoft.com> wrote: > If any of the operands of == or != are typed to dynamic C# emits a call > to dynamic site with the corresponding operation. If the left hand side is a > Ruby object then this dynamic operation is translated to a Ruby method call > “==” or “!=”, respectively. > > The latest version of IronRuby (built from github sources) is compatible > with MRI 1.9.2 in the way “!=” method is implemented: BasicObject#!= calls > == and negates the result. You can also provide your own implementation of > != method if its behavior should be different. This semantics is compatible > with DLR dynamic operations and everything works as expected: > > > > dynamic equatable = Engine.Execute(@" > > class RubyEquatable > > def initialize val > > @val = val > > end > > > > def ==(other) > > @val == other > > end > > end > > > > RubyEquatable.new(100) > > "); > > > > Assert((bool)( equatable == 100)); > > Assert(!(bool)( equatable == 101)); > > Assert(!(bool)( equatable != 100)); > > Assert((bool)( equatable != 100)); > > > > Tomas > > > > *From:* ironruby-core-boun...@rubyforge.org [mailto: > ironruby-core-boun...@rubyforge.org] *On Behalf Of *Davy Brion > *Sent:* Thursday, September 09, 2010 4:46 AM > *To:* ironruby-core@rubyforge.org > *Subject:* Re: [Ironruby-core] object equality > > > > > > On Thu, Sep 9, 2010 at 1:44 PM, Davy Brion <ral...@davybrion.com> wrote: > > by default, == does a reference check in C#, unless you override it to do a > value based check (which you typically implement in Equals) > > in C#, if you want == and != to work properly you need to implement them > both. In ruby, you obviously can't implement !=, but i had (naievely > perhaps) expected that IronRuby would preserve the Ruby behavior when > calling == on an object which implements it. I _think_ that would be the > best way to handle this, though there might be very valid reasons as to why > this isn't the case at the moment. > > defining an Equals method on the ruby class which delegates to == works, > but it is somewhat weird since most people use the == and != operators to > check for equality. > > perhaps i'm better off getting rid of the == implementation and solely > providing an Equals implementation > > > > > though the downside of that is that the ruby class doesn't stick to ruby's > idioms when it comes to equality checks, which hurts its usage from other > ruby code :s > > > > > On Thu, Sep 9, 2010 at 1:10 PM, William Green <w...@hotgazpacho.org> > wrote: > > Then it would appear that in C#, using the != operator on two instances of > Ruby objects does not call the == method on the first Ruby object and invert > the result. > > > > Can you switch to using equals as a work-around? > > > > Not sure of the semantics around == vs .Equals in C#, but I know there is a > semantic difference between == and eql? in Ruby. > > > -- > > Will Green > > http://hotgazpacho.org/ > > > > > > > On Sep 9, 2010, at 6:52 AM, Davy Brion <ral...@davybrion.com> wrote: > > the problem isn't with checking wether 2 objects are equal (though you > indeed need to define an Equals method on your ruby object if you want the > comparison to work with a direct call to .Equals... doing == in C# > definitely uses the == method of your ruby object) but it is with the != > check. In ruby, using != calls == and inverts the result of that. Doing != > in C# on a ruby object doesn't seem to do the same thing. > > I'm also not entirely sure how it _should_ be... but as far as i can tell, > right now, i can't get equality checks working properly with ruby objects. > > if a == b is true, then a != b should always be false > if a.Equals(b) is true, then !a.Equals(b) should always be false > > if there's another way to get this behavior working in C# for ruby objects, > i'd love to hear about it since it's pretty important for something i'm > trying to do :) > > On Thu, Sep 9, 2010 at 12:20 PM, William Green <w...@hotgazpacho.org> > wrote: > > Testing for object equality in C# is different than it is in Ruby. In > C#, you need to override both Object.Equals and Object.GetHashCode (I > forget which is used when, but I do recall that the compiler complains > if you override one and not the other). So, when you bring your Ruby > object into C# and compare them, C# doesn't see an override for Equals > on your object, and thus uses Object.Equals (which is often what you > don't want). Try defining an equals method on your Ruby object, or > alias it to ==. > > I suspect that the == method on your Ruby object does not map to > Equals when you bring into C#. And I'm not sure that it should. > > Thoughts? > > -- > Will Green > http://hotgazpacho.org/ > > > > > On Sep 9, 2010, at 4:33 AM, Davy Brion <ral...@davybrion.com> wrote: > > > If i have the following class in ruby: > > > > class TestClass > > def initialize(value) > > @value = value > > end > > > > def ==(other) > > return false if other.nil? > > self.value == other.value > > end > > > > protected > > > > def value > > @value > > end > > end > > > > test1 = TestClass.new(5) > > test2 = TestClass.new(5) > > p test1 == test2 > > p test1 != test2 > > > > the output is: > > true > > false > > > > if i do this in .NET: > > > > dynamic test1 = ruby.testcla...@new(5) <ruby.testcla...@new%285%29>; > > dynamic test2 = ruby.testcla...@new(5) <ruby.testcla...@new%285%29>; > > > > var equals = test1 == test2; > > var differs = test1 != test2; > > > > both equals and differs are true > > > > i'm going to create an issue about this, but i do need to get this > working... is there a temporary workaround that i can use for now? > > > _______________________________________________ > > Ironruby-core mailing list > > Ironruby-core@rubyforge.org > > http://rubyforge.org/mailman/listinfo/ironruby-core > _______________________________________________ > Ironruby-core mailing list > Ironruby-core@rubyforge.org > http://rubyforge.org/mailman/listinfo/ironruby-core > > > > _______________________________________________ > Ironruby-core mailing list > Ironruby-core@rubyforge.org > http://rubyforge.org/mailman/listinfo/ironruby-core > > > _______________________________________________ > Ironruby-core mailing list > Ironruby-core@rubyforge.org > http://rubyforge.org/mailman/listinfo/ironruby-core > > > > > > _______________________________________________ > Ironruby-core mailing list > Ironruby-core@rubyforge.org > http://rubyforge.org/mailman/listinfo/ironruby-core > >
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