Re: [Pyobjc-dev] [ pyobjc-Bugs-678818 ] Missing NSCFNumber to int conversions

[Ronald O. <ous...@ci...>]

On Sunday, Feb 2, 2003, at 00:15 Europe/Amsterdam, bb...@ma... wrote:

> On Saturday, Feb 1, 2003, at 17:16 US/Eastern, SourceForge.net wrote:
>> 1. if x: should only execute the if clause when x is
>> nonzero.  But if x is a zero NSCFNumber, the clause
>> gets executed erroneously (third line of code's output
>> is "Increment by ..." instead of "Null increment")
>
> I believe this is working correctly on my system?
Probably because I checked in a fix for this just before the weekend 
:-) NSCFNumber evaluates to true if the value returned by 'boolValue' 
does (as do all other objects that have a boolValue method)

>
> [bumbox:~/bbum-developer/sourceforge/pyobjc] bbum% python foo.py
> Increment by 3 to 3
> Null decrement to 3
> Null increment to 3
> Decrement by <NSCFNumber objective-c instance 0x470330> to 0
>
>> 2. str(x) should produce a decimal representation of x,
>> but if x is an NSCFNumber, it instead produces a string
>> like '<NSCFNumber objective-c instance 0x832ed0>'
>> (third and fourth lines of code's output).
>
> This is definitely broken.  Both str() and repr() do not do what one 
> might expect.
>
> Why doesn't str() invoke -description?  ...or repr()?  __repr__ 
> mapping to -description was commented out of _convenience.py.

I have no idea why this was removed. ... Oh, I do know: If you invoke 
-description from __str__ and __repr__ you may cause a coredump if you 
do something like this in an interactive interpreter:
	>>> NSSomeClass.alloc()
	<NSSomeClass instance at 0xabcdabcd>
	>>> _.init()
	<NSSomeClass instance at 0xabcdabcd>

For some values of 'NSSomeClass' the interpreter will crash when trying 
to print the repr of the return value of alloc. The interpreter seems 
to call __repr__, so we should be safe if we only map __str__ to 
description.

Ronald