coercion

[tim lindner]

I have a question about coercion:

% (set num 10)
10
% (set str "hello")
"hello"
% (str appendString:num)
2009-08-18 11:49:50.845 nush[5207:10b] *** -[NSCFNumber length]:
unrecognized selector sent to instance 0x252450
NSInvalidArgumentException: *** -[NSCFNumber length]: unrecognized
selector sent to instance 0x252450

I changed it to:

% (str appendString:(+ "" num))
()
% str
"hello10"

Is there a better way?

[Tim Burks]

You could instead use (num stringValue)

In your case, the appendString: method is defined in the frameworks
and expects an object that responds to NSString methods. It might be
possible to add other methods to NSNumber to get that to work
automatically, but for now, sending the stringValue message will do
the job.

Tim