Go easy on the newbies, ok? :) We were all there once... It's been YEARS,
but I recall being completely lost with collections and "which ones to use and
how." You are indeed correct about non-newbs needing to make sure that any
errors are gracefully presented vs. taking out the vm.
Bill
________________________________________
From: pharo-project-boun...@lists.gforge.inria.fr
[pharo-project-boun...@lists.gforge.inria.fr] on behalf of Andrew P. Black
[bl...@cs.pdx.edu]
Sent: Monday, January 30, 2012 1:31 PM
To: Pharo Project
Subject: [Pharo-project] Collection new
Teaching a class of novices, it's not surprising that someone tried "Collection
new". What was surprising is that this got the VM is a loop of some kind, with
emergency stack dumps and so on.
Here is my reply:
> On 30 Jan 2012, at 01:18 , Xingzhi Harry Pan wrote:
>
>> ...it's pretty innocent:
>> Collection new
>
>
> OK. I looked at this. The problem comes when trying to print the collection.
> Somehow the VM gets confused when trying to do do: ... I'm not quite clear
> why.
>
> The quick fix is to change the Collection>>new method to
>
> self error: 'Collection is an abstract class, and cannot be
> instantiated'
>
> However this will break Heap>>new: , which sends super new. It ought to send
> self basicNew instead.
>
> These two changes seem to avoid the problem, but I'm waiting to see ...
>
> Andrew
But I don't understand the root cause. Printing eventually sends do:, which is
self subclassResponsibility. Why don't we get a clean failure?
Andrew
