On 12-Aug-08, at 2:30 AM, Tony Garnock-Jones wrote:

> Yes, an error is currently signalled. Which makes the general case:
>
> aCollection ifEmpty: [0] ifNotEmpty: [aCollection sum].
>
> .. which, to me, is a bad code smell. Then again, I've been an FPer  
> for a long while.

It's a code smell from an OO perspective too.

This is  a bit like the #join: debate that comes up every now and then  
when a Ruby/Python/Perl ex-pat asks how it is that we don't have  a  
method for joining an array of strings into a single string. The short  
answer is that it's because #join: only makes sense when all the  
elements of a collection are strings, and therefore, it's bad design.

This is similar. I'd say the best way to improve #sum would be to  
delete it.

Ok, compatibility is an issue, breaking existing code would be bad  
etc. So leave it as is and point anyone who complains to  
#inject:into:. If that's really too verbose, then what's really needed  
is a more specific class that understands what this collection of  
numbers represents.

Colin