Haha, great discussion, great find. Amazing that all these things are just already there.
Pharo/Smalltalk programming is really 'studying the problem and the existing system, moving it to the desired state with as little work as possible' - including the use of frameworks and libraries. > On 29 Mar 2019, at 18:08, Peter Kenny <pe...@pbkresearch.co.uk> wrote: > > 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
