Re: [Pyobjc-dev] Calling methods on nil

[Just v. R. <ju...@le...>]

Dinu Gherman wrote:

> Ok, I'm looking deeper into the documentation.... so here we go!
> Item 2 in pyobjc/Doc/warts.html currently says:
> 
>    In objective-C it is valid to call methods on nil, these calls
>    will be ignored. The nil 'object' is mapped to None and None
>    will not ignore method calls, but will most likely raise an
>    AttributeError. You'll have to remember this when translating
>    from Objective-C to python.
> 
> This might lead to people who are trying to convert Cocoa code to
> Python to change the application logic. I remember I wrote a Null
> class that would behave as much as a "black whole" as possible.
> It's in the O'Reilly Python Cookbook and available online here:
> 
>    http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/68205
> 
> This might benefit from some more detailed inspection using ver-
> sion 2.3 of Python, which I haven't done, yet.
> 
> I might be possible to replace the current None (as currently con-
> verted from nil) with a singleton Null instance, possibly as an
> option only, if the code rewriting ever becomes more of a real
> issue... I know that it can be very convenient in some cases if
> "nothing" happens in a well-defined way! ;-)

-1. It may be the ObjC way, but it's not the Python way. Remember we're
using Python to use Cocoa and not to write ObjC with a nicer syntax...

Just