Please fill in a bug report in bugs.squeak.org
2007/3/21, brad fowlow fowlow@pacbell.net:
Howdy folks.
A bit of collection trivia...
Collection ifEmpty: [ foo ] returns nil if the collection is not empty, owing to the placement of the return in
ifEmpty: aBlock "Evaluate the block if I'm empty" ^ self isEmpty ifTrue: aBlockIt would be a tad less efficient, but (I think) more useful to say ifEmpty: aBlock self isEmpty ifTrue: [ ^ aBlock value ]
returning the original collection if non-empty, ... since this allows expressions such as
foo := (collection allAfterLast:'@') ifEmpty: [collection]. This will only work if you add a cumbersome ifNotEmpty:[:c|c] to the end, to force the result value to be the non-emptyallAfterLast:
My Squeak (3.8.something, a Croquet image) has 18 uses of isEmpty:, none of them using the result.
Of course it's very unlikely anyone would arrange a platform change of this sort for such a trivial thing. But the ifEmpty: methods appear to be of later vintage than a lot of the core of Collection.
And usually, I find that the methods in the basic system are well thought out to suit a wide range of use patterns; this seemed like an odd exception.
So... a question for the tidy expression fans.... what's a nice tidy ordered-collection expression for everything after x, unless there is no x, in which case all since I'm probably just looking into my blind spot, overlooking something obvious.
Regards, brad