On 19 July 2013 12:05, Nicolas Cellier
<nicolas.cellier.aka.nice at gmail.com> wrote:
> First, let's forget about OrderedCollection, that's just Levente's post that
> misguided me.
> The old behaviour was to return an Array, so you couldn't add: either.
>
> In your example, you explicitely asked for an Array, then you select: an
> Array, that seems fair.
> I see no reason why we would change that to a String.
>
> That's different from ($a to: $z) case where we did not explicitely
> requested an Array.
> Some code does indeed implicitely expect an Array, and I broke it, because
> - as you said, it's hard to analyze source (many senders)
> - and as we all know, we lack a few tests here and there (well, it's a joke,
> we lack more than we have, but that's a debt from the past that we slowly
> refund)
>
> But let's return to these expectations.
> An Array of Character has not much value per se. I mean that's exactly what
> a String is, an Array of Character...
> Except that the String is much much reacher with a bunch of specialized
> methods (because we know it contains Character).
> So to me, the most logical thing to do remains to answer a String.
> I'm not the only one to share this logic, look what Character class methods
> do:
>
> {Character alphabet. Character separators. Character allByteCharacters}
> collect: #class as: Set
>
> The only difference with String is when you collect: something else than
> Character, and that's what you bumped into.
> But as Levente said, we have very convenient collect:as: for this special
> case.
> So, I agree that I changed the contract and broke some code, but that's an
> easy to fix and probably rare problem.
> To me the balance benefits/costs is fair.
>
> This knowledge should go into some realease notes at least, in order to ease
> upgrades.
> But we are not yet at this level of maturity...

Sure we are! Add the note to http://wiki.squeak.org/squeak/6189 and
when 4.5 gets released the release manager will have a nice lump of
text to add to the "what's new" window.

frank

> Cheers
>
>
>
> 2013/7/18 tim Rowledge <tim at rowledge.org>
>>
>>
>> On 18-07-2013, at 3:47 AM, Nicolas Cellier
>> <nicolas.cellier.aka.nice at gmail.com> wrote:
>> > I did the change and the rationale is that the most logical Collection
>> > recipient for Character is String, what else?
>>
>> I'm not at all sure I agree there; yes, as mentioned before a String is a
>> collection of Characters in some sense - but one should also consider an
>> Interval as an Array that is specified by shorthand that relies on a known
>> ordering. If we wrote
>> (Array with: $a with: $b with: $c) select:[:c| c =$b]
>> should we get #($b) or 'b' ? I think #($b) is correct.
>>
>> > OrderedCollection is totally arbitrary with this respect.
>> > OK, you cannot add: to a String. But can you add: to (1 to: 10)? No you
>> > can't.
>>
>> That's why #species is there - to provide a suitable recipient for the
>> results of enumerations when running over such objects.
>>
>> > So, put together, the Rationale is simply a principle of least
>> > astonishment.
>>
>> The practical problem is that even though I'm sure you looked to see what
>> problems the change might cause  - because you're nice (how often do I get
>> to make a fun pun on someone's name?) - you can't easily be sure that you
>> can even see all the places where it might be troublesome. It broke a
>> relatively basic tool that I stumbled upon because it is mentioned in a
>> tutorial. How can we feel sure it doesn't affect other bits of code? I don't
>> think it's terribly practical to search out every use of #to: (or other
>> Interval creation methods) and then dig around to find out how it got used
>> subsequently, it's simply too common an idiom. Within one's own special code
>> it can still be tricky if the project has grown large (ask me about grokking
>> Scratch…) but in the general case? Forget it, unless somebody has a project
>> to really, truly automate it. And in all the cases where we didn't catch the
>> problem, somebody is going to be unpleasantly astonished.
>>
>> tim
>> --
>> tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
>> No, I don't explode cats. It's way too difficult to coax them into the
>> microwave - http://tinyurl.com/yp3hgr
>>
>>
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