[Ironpython-users] Why does this happen?

[Slide]

Here's the expression for my case

{IIF(CallSiteBinder(Convert($arg0).__eq__(Convert(Unbox($arg1)))), 0,
IIF(CallSiteBinder(op_LessThan(Convert($arg0),
Convert(Unbox($arg1)))), -1,
IIF(CallSiteBinder(op_GreaterThan(Convert($arg0),
Convert(Unbox($arg1)))), 1, IIF((Not(((coerceResult =
Convert($arg0).__coerce__(value(IronPython.Runtime.CodeContext),
Convert(Unbox($arg1)))) Is OldInstance)) AndAlso ((coerceTuple =
ValidateCoerceResult(coerceResult)) != null)), {var callres; ... },
Convert(Convert($arg0).__cmp__(value(IronPython.Runtime.CodeContext),
Convert(Unbox($arg1))))))))}

Here is the expression for the List.sort case

{IIF((Not(((coerceResult =
Convert($arg0).__coerce__(value(IronPython.Runtime.CodeContext),
Convert($arg1))) Is OldInstance)) AndAlso ((coerceTuple =
ValidateCoerceResult(coerceResult)) != null)), {var callres; ... },
Convert(Convert($arg0).__cmp__(value(IronPython.Runtime.CodeContext),
Convert($arg1))))}

Is there more information from the DynamicMetaObject that would be helpful?

Thanks for your time, I appreciate you helping out those like me who
don't know much about the internals of IronPython.

slide


On Thu, Mar 29, 2012 at 10:07 PM, Dino Viehland <dinov at microsoft.com> wrote:
> I'm actually not sure why it would happen.  The only thought I have is if you're
> only doing one comparison, and comparing the same instance, there's an object
> identity test which would prevent the __cmp__ call from happening.  But I'm guessing
> that's not what's happening...
>
> Can you put a breakpoint in PythonProtocol.Operations.cs in MakeSortComparisonRule
> and see what's returned from the call to bodybuilder.GetMetaObject?  That'll give you
> the full expression tree of the rule for doing the comparison.  There's supposed to be
> some calls to __cmp__ in there - if they're not there maybe what is will provide some
> enlightenment.
>
>> -----Original Message-----
>> From: ironpython-users-bounces+dinov=microsoft.com at python.org
>> [mailto:ironpython-users-bounces+dinov=microsoft.com at python.org] On
>> Behalf Of Slide
>> Sent: Thursday, March 29, 2012 8:49 PM
>> To: ironpython-users at python.org
>> Subject: Re: [Ironpython-users] Why does this happen?
>>
>> Is Dino on vacation? He usually has good answers for these sorts of things :-) I
>> still can't get the callsite to end up calling __cmp__ like List.sort does. I'm not
>> sure why that is the case. It looks like even the Python version of bisect has a
>> similar issue though (it never calls __cmp__ either), so I think there is a bug
>> somewhere.
>>
>> On Sat, Mar 24, 2012 at 8:51 PM, Slide <slide.o.mix at gmail.com> wrote:
>> >
>> > I am implementing a module in C#. This module does some comparison
>> operations. One of the tests for this module has something like the following:
>> >
>> > class CmpErr:
>> >     def __cmp__(self, other):
>> >         raise ZeroDivisionError
>> >
>> > x = [CmpErr(), CmpErr(), CmpErr()]
>> > cSharpMethod(x)
>> >
>> > Inside cSharpMethod is when I do the comparison. The way I am doing
>> > the comparison is taken from how its done in List.cs
>> >
>> > IComparer comparer =
>> > PythonContext.GetContext(context).GetComparer(null,
>> > GetComparisonType(context, list));
>> >
>> > Then I call comparer.Compare on the two items. In List.sort, this eventually
>> calls the __cmp__ method if I try adding a call to x.sort() instead of
>> cSharpMethod, but from inside cSharpMethod, __cmp__ is never called and I
>> can't figure out why.
>> >
>> > Any ideas on why this might be occuring?
>> >
>> > Thanks,
>> >
>> > slide
>> >
>> > --
>> > Website: http://earl-of-code.com
>>
>>
>>
>>
>> --
>> Website: http://earl-of-code.com
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>
>



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