Finally merged via Collections-mt.1009 and CollectionsTests-mt.376.
The #old* interface is not yet deprecated but tested.
Best, Marcel Am 09.08.2020 00:10:20 schrieb David T. Lewis lewis@mail.msen.com: On Sat, Aug 08, 2020 at 04:21:27PM -0500, Chris Muller wrote:
I can see the nil being returned there explicitly, so that's "where it's
happening." Should this be the case though?
The previous, probably original implmenetation of #peekBack used to send #oldBack to the stream. IIRC #oldBack was based on the idea that the position of a stream is an index of a sequence where #next means +1 to that index while #back means -1 to that index. Following that logic, you have to #skip: -2 and send #next to get the element -1 to position.
#oldBack has been removed but the behavior of #peekBack is presumably the same as it was before. Some ancient but now external code may rely on #peekBack but it's not very likely such code would work in the current Trunk. #peekBack has no real users in the Trunk only a test remembers what it used to do.
Given the above, and given that we have #next:, I ended up balancing that API with #peek:, and that again with #peekBack:. Since they all simply return a String, possibly empty, they dodge the question about nil vs. error entirely.
So, I think it's a good time to change its behavior to be based on #back.
Without wanting to sound ungrateful for Eric's contribution (of which I look forward to more of), may we also consider the addition-by-subtraction opportunity? I mean, it kinda makes sense that there wouldn't, and won't, be any users of #peekBack. Maybe we should deprecate it.
That's probably the best idea of all.
As far as I can tell, #peekBack was used in PositionableStream>>#backChunk in the Squeak 3.8 era, but Levente's 3/22/2010 version of the method in trunk today eliminated the need for it.
So given that nobody uses it and we don't know how it should work, +1 for deprecation.
And +1 to looking forward to more contributions from Eric :-)
Dave