Tim Going back to your original question, the answer is there all the time but buried in the enormous method dictionaries of the Collection subclasses. If you look at SequenceableCollection>>atWrap: you will see that it does exactly what you want.
To get the item before the first, i.e. the zeroth: #(1 2 3 4) atWrap: 0 => 4 To get the item after the last: #(1 2 3 4) atWrap: 5 => 1 As seen here, the method is inherited by Array, so it should do all you want. HTH Peter Marcus Denker-4 wrote >> On 29 Mar 2019, at 14:24, Ben Coman < > btc@ > > wrote: >> >> >> >> On Fri, 29 Mar 2019 at 18:57, Tim Mackinnon < > tim@ > > wrote: >> Hi Peter - yes of course you are right that its malleable, I guess I’m >> often suprised about the things we leave out and then discover weird >> things we’ve put in. >> >> I had a quick look at LinkedList (I should have thought of that) - I >> might be able to do something with that (and this is now more out of >> curiosity) - but gosh its an easy way to crash your image. Having linked >> the first to the last, and then tried a quick: list after: $n - I’m now >> guessing I’m stuck in an infinite loop that even Cmd . won’t break out >> of!!!! ouch. >> >> If you look at Hier(archy) of LinkList you'll see Semaphore underneath >> it. >> I'm not sure, but there may be some VM magic around Semaphore and Process >> management that makes it fragile to changes. >> I believe there have been some proposals to separate out the Process >> related LinkedList stuff, but I can't remember the exact arguments. > > Yes, we did that… there is now ProcessList. > > We ran into that problem far too often “hey, LinkedList can be cleaned up > easily like this!” —> boom, everything broken. > > Now we have ProcessList where it matters if code is changed to introduce a > message send more and LinkedList where it does not. > > Marcus -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html
