[ENH] ifNotEmptyCleans

Marcus Denker denker at iam.unibe.ch
Thu Sep 30 11:56:58 UTC 2004


Am 30.09.2004 um 13:24 schrieb Avi Bryant:

>
> On Sep 30, 2004, at 12:41 PM, stéphane ducasse wrote:
>
>> For me I do not understand what it means to require an argument, in 
>> this case this is not
>> 	ifNotEmpty: [do that]
>> 	but ifNotEmpty: [do that with self]
>> and the message does not tell that at all
>>
>> and why we have that for ifNotEmpty and not for ifTrue: and isNil:
>
> Because in the case of ifTrue: and ifNil: (as well as ifFalse:), if 
> the block is evaluated then you know exactly what the receiver is, so 
> there's no need to pass it in.
> This is also mostly true for #ifEmpty:, in that you know that you've 
> got an empty collection, and that's probably all you care about.  In 
> the case of #ifNotNil: or #ifNotEmpty:, however, there are interesting 
> things about the receiver (for #ifNotNil:, what the instance is, for 
> #ifNotEmpty:, what instances it contains) that you *don't* know, and 
> so passing the receiver into the block is very useful.
>
> I generally agree with you about the message names, in that I'd rather 
> see ifNotEmptyDo: (to match #ifNotNilDo:) as a distinct method from 
> #ifNotEmpty:.  However, there's a compatibility issue here - other 
> dialects expect #ifNotNil: and #ifNotEmpty: to take a 1-arg block, and 
> we should probably follow suit.  As it is I have to avoid using either 
> message if I want my code to be portable, which is a shame.
>

So I think the following would be a good compromise:

1) allow 0- and 1-arg block for ifNotEmpty: and ifNotNil: for 
compatibility
2) provide ifNotEmptyDo: to be used. (there is already ifNotNilDo:).


         Marcus





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