On Sat, 08 Sep 2007 20:00:32 +0200, Philippe Marschall wrote:

> 2007/9/8, Klaus D. Witzel:
>> Hi,
>>
>> Math and I discuss comparing two CompiledMethods whether or not they
>> represent the same object when compiled from source. This is necessary  
>> for
>> writing tests for the Decompiler.
>>
>> One of the obstacles are certainly the methods' literals, in particular
>> Float>>#nan which have to be treated equal in the two compared methods,
>> regardless of the fact that (Float nan = Float nan) == false :)
>
> How can you normally end up with a NaN literal? (Without messing with
> the compiler, modifying literal arrays or stuff like that).

Float>>#nan
	"Answer the canonical value used to represent Not-A-Number"

	^ NaN

/Klaus

> Cheers
> Philippe
>
>> Are there other cases which should be considered, for example does  
>> someone
>> expect that Float>>#closeTo: is used for comparing Float literals of two
>> methods? If that's not the case then Float literals other than nan, can  
>> be
>> compared with good old fashioned #=.
>>
>> FWIW the two methods could have been compiled by different compilers
>> and/or have literals (for example in class vars) created by different
>> readers (think of Number#>>readFrom:), makes writing tests for the
>> Decompiler not that easy :|
>>
>> TIA.
>>
>> /Klaus
>>
>> On Sat, 08 Sep 2007 17:30:37 +0200, Alejandro F. Reimondo wrote:
>>
>> >
>> >> Ok any reason for that?
>> > Yes. "nan" is not an object (it does not preserve identity),
>> >  it is something that can be named and that preserve
>> >  behavior (we can draw/attach an interface for/to it),
>> >  those properties does not make it an object.
>> >
>> > Ale.
>> >
>> >
>> >
>> > ----- Original Message ----- From: "Mathieu Suen"  
>> <mathk.sue at gmail.com>
>> > To: "The general-purpose Squeak developers list"
>> > <squeak-dev at lists.squeakfoundation.org>
>> > Sent: Saturday, September 08, 2007 9:48 AM
>> > Subject: Re: Float>>nan
>> >
>> >
>> >> Ok any reason for that?
>> >>
>> >> Mth
>> >>
>> >>
>> >>
>> >> On Sep 8, 2007, at 12:24 PM, Lukas Renggli wrote:
>> >>
>> >>>> I have a strange bug:
>> >>>>
>> >>>> Float nan = Float nan -> false
>> >>>
>> >>> According to the standard NaN is not be equal to anything,   
>> including
>> >>> itself.
>> >>>
>> >>> Check: http://en.wikipedia.org/wiki/IEEE_754
>> >>>
>> >>> Lukas
>> >>>
>> >>> -- Lukas Renggli
>> >>> http://www.lukas-renggli.ch
>> >>>
>> >>
>> >>
>> >
>> >
>> >
>>
>>
>>
>>
>
>