On 31 January 2013 22:59, Frank Shearar <frank.shearar at gmail.com> wrote:
> On 30 January 2013 20:04,  <commits at source.squeak.org> wrote:
>> Frank Shearar uploaded a new version of Kernel to project The Inbox:
>> http://source.squeak.org/inbox/Kernel-fbs.736.mcz
>>
>> ==================== Summary ====================
>>
>> Name: Kernel-fbs.736
>> Author: fbs
>> Time: 30 January 2013, 8:04:08.926 pm
>> UUID: 1d99c937-4c68-475c-987b-2990c8040c29
>> Ancestors: Kernel-fbs.735
>>
>> Rename NotImplemented errors in line with conventions 2 of 3.
>>
>> =============== Diff against Kernel-fbs.735 ===============
>
> If folks are happy with what I've got, I'd like to make one more
> change, and remove NotYetImplemented>>#defaultAction. This will make
> this message send open up a Debugger. Then I just need to tweak the
> Debugger to show the Create button.
>
> If people think that's sensible I'll make the change and resubmit,
> clearing out obsolete Inbox ancestors to show a more complete diff.

Actually, I'm going to hold off on touching NotYetImplemented. I think
it's a good idea to remove the default action, but it and
#shouldBeImplemented have a wrinkle that I can't see right now how to
fix.

Let's say you have Bar >> #ff [ self notYetImplemented ]. You evaluate
`Bar new ff` and the Debugger pops up, asking if you want to create
that method. You enter the desired behaviour - `^ 1` - and accept. The
stack now looks like this:

Bar >> #ff (containing `^ 1`)
Bar >> #ff (containing `self notYetImplemented`)
<the topmost frame of the rest of the stack>
<the rest of the stack, ending in a DoIt>

The topmost context returns, and _retriggers_ the exception. Instead,
we should _discard_ the `self notYetImplemented` stack frame and have
the new implementation return its result to <the topmost frame of the
rest of the stack>.

It's probably not even hard, but my brain's a big mushy.

So instead I'd like to merge what I have, and add as a separate enhancement
* removing NotYetImplemented >> #defaultAction
* returning to the sender sender context, <the topmost frame of the
rest of the stack>.

This latter step should also avoid the problem of people not writing
their stubs as `^ self subclassResponsibility`, which prevents
seamlessly progressing with one's computation. (If you don't say `^`
then your new result-returning implementation returns its result to
the non-`^` stub/marker context, which returns self.)

I want the experience of implementing missing functionality to be
almost like rewriting history - "we have always had this
implementation of this message". (To be read in the same voice as "We
have always been at war with Eurasia.")

frank