[squeak-dev] PositionableStream >> peekBack
btc at openinworld.com
Fri Jun 30 01:36:15 UTC 2017
On Fri, Jun 30, 2017 at 5:56 AM, Nicolas Cellier <
nicolas.cellier.aka.nice at gmail.com> wrote:
Strangely, I can't shake the idea this is a good name for a SciFi Thriller
> we can't reasonnably drag too many of these inconsistencies...
> 2017-06-22 5:48 GMT+02:00 Ben Coman <btc at openinworld.com>:
>> When I read that first line of your post, my impression/expectation was
>> the same as yours.
>> Intuitively #back and #peekBack should return the same value.
>> But my comments are face-value only, without a deep familiarity of
>> streams. Maybe someone else can provide historical & future context.
>> Presuming it was broadly accepted this "should" be the behaviour of
>> #peekBack, the problem with changing its behaviour is the effect on
>> existing users, and also cross-dialect compatability. "Ideally" Squeak/Cuis
>> would be ammendable to such a change, and then one approach could be a
>> little dance using an interim #peekBackFromCursor so the existing #peekBack
>> can be deprecated for one version (to avoid silent corruption of
>> application logic) then restoring #peekBack with the new behaviour. A
>> slow process, but such small changes accumulate over time to improve things.
>> Alternatively, we just leave #peekBack as-is and permanently introduce
>> #peekBackFromCursor or similar.
>> Maybe such changes would be superseded by XStreams anyway (not really a
>> reason stop improving current system anyway.)
>> cheers -ben
>> On Wed, Jun 21, 2017 at 9:00 PM, Jakob Reschke <
>> jakob.reschke at student.hpi.de> wrote:
>>> Hi all,
>>> I just stumbled upon the behavior of #peekBack. I expected that it
>>> would give me a "preview" of what I would get when I send #back, but
>>> without changing the position of the Stream (like #peek does for
>>> #next). Or in other words, I expected to get the last read (or
>>> written) element.
>>> As it turned out it answers the next-to-last element instead. There
>>> even is a test case in RWBinaryOrTextStreamTest for this behavior.
>>> But does it make sense? I have my doubts mainly because of the
>>> inconsistency with the return value of #back.
>>> There is also #peekLast, which does what I expected, but it is only
>>> defined for File- and WriteStream and the comment says it is intended
>>> to get the last put element, not a last read/extracted/next-ed
>>> Kind regards,
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the Squeak-dev