Hi Marcus - that’s actually what I do - and “create” in this case, creates a 
class and then restarts like the method case does.

I guess I was wondering if we can do it more cleanly and also improve the 
debugger message. 

If I’ve understood you guys correctly- you try to remove the ambiguity around 
operations. Looking up a class and getting nil - seems like one of these holes 
you keep sorting out.

I think the flaw in my solution is understanding if that message was being sent 
to a class, or some other global? I dont think I got that bit right (but it’s 
certainly better than nothing).

e.g. in the debugger I am doing (in DoesNotUnderstandDebugAction) 

msg := self interruptedContext tempAt: 1.
(msg lookupClass == UndefinedObject ) ifTrue: [ 
        ^self createMissingClassIn: self interruptedContext ].


I’m not totally convinced that lookupClass has to be a class - although maybe 
its good enough. But really, at the time this happened - we probably knew 
better than to get a DNU debug action in the the first place - and equally the 
title in the debugger could be something more akin to the kind of action its 
supposed to be.

Anyway - this is all musing on my part - and I will assemble a proper PR for 
review by you guys (and at least it advances us forward - and maybe opens the 
door to better changes further on).

I’m just juggling another change at the moment - so it will be a few days.

Tim

Sent from my iPhone

> On 23 Aug 2018, at 05:33, Marcus Denker <marcus.den...@inria.fr> wrote:
> 
> 
> 
>> On 22 Aug 2018, at 16:24, Tim Mackinnon <tim@testit.works> wrote:
>> 
>> Hi - but I guess my question is (and excuse my basic knowledge in this area) 
>> - when a class isn’t found - can we do better than return nil so that the 
>> debugger can give a better msg and presumably the code I’ve written could 
>> live on that undefined object? Or am  thinking about this wrong?
> 
> In pharo7 we could easily do that (due to the “binding”, the meta class of 
> the variable) being different. We could return a nil subclass or add code 
> into the method directly. But the problem with that is that nil checks
> are always identity checks… 
> 
> Could you not in the case you now raise the error just fall back to the 
> “define method”, the behaviour we have now? 
> 
>   Marcus
> 
>> 
>> I will also put together a pr for this in Pharo 7 if you think it’s a decent 
>> fix.
>> 
>> Tim
>> 
>> Sent from my iPhone
>> 
>> 
>> 
>> Sent from my iPhone
>>> On 22 Aug 2018, at 09:51, Marcus Denker <marcus.den...@inria.fr> wrote:
>>> 
>>> Hi,
>>> 
>>> I played with it, nice!
>>> 
>>> I guess the case when you really get a DNU on nil (and want to create  
>>> method there) does not really happen… extending nil is for special cases.
>>> 
>>> Marcus
>>> 
>>> 
>>>> On 22 Aug 2018, at 13:39, Tim Mackinnon <tim@testit.works> wrote:
>>>> 
>>>> Sorry Marcus - you needed to follow the exercism instructions and right 
>>>> click on the exercism package to get an exercism menu to fetch a new 
>>>> exercise (e.g. hello-world). The is then using the TonalReader to pull in 
>>>> code - and then you get a test class that can reference a class that isn’t 
>>>> there yet. (But you need to have the exercism cli installed as per the 
>>>> instructions etc).
>>>> 
>>>> In retrospect I think it might be simpler to download this 6.1 image that 
>>>> already has done that - 
>>>> https://www.dropbox.com/s/x2ot9f8arbbvlyb/PharoExercism.zip?dl=0
>>>> It has TwoFerTest that is in that state. If you click on the  TestWithName 
>>>> orb, you will see "#new was sent to nil” - can you can see how my Create 
>>>> button has been fixed per you suggestions to create a class. (The code I 
>>>> wrote is in 
>>>> ExercismTools:DoesNotUnderstandDebugAction>>createMissingClassIn:)
>>>> 
>>>> Tim
>>>> 
>>>> 
>>>>> On 22 Aug 2018, at 04:44, Marcus Denker <marcus.den...@inria.fr> wrote:
>>>>> 
>>>>> 
>>>>> 
>>>>>> On 17 Aug 2018, at 14:20, Tim Mackinnon <tim@testit.works> wrote:
>>>>>> 
>>>>>> The direct link to instructions is here: 
>>>>>> https://exercism.io/tracks/pharo/installation (not sure if you have to 
>>>>>> be signed up to see it otherwise its in the repo here: 
>>>>>> https://github.com/exercism/pharo/blob/master/docs/INSTALLATION.md)
>>>>> 
>>>>> Hm… AllExercismTests seems to not be there (just a green test in Welcome)
>>>>> 
>>>>> Is this supposed to contain the code below (the 
>>>>> createMissingClassActionFor:in:) ?
>>>>> 
>>>>> It would be nice to have an image that shows exactly the problem (I do 
>>>>> not have  that much time sadly to work on it,but I do have some time to 
>>>>> check if I have an image that is set up to the point where i can easily 
>>>>> recreate the problem)
>>>>> 
>>>>> Marcus
>>>>> 
>>>>> 
>>>>>> Tim
>>>>>> 
>>>>>>> On 17 Aug 2018, at 07:17, Marcus Denker <marcus.den...@inria.fr> wrote:
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>>> On 17 Aug 2018, at 13:00, Tim Mackinnon <tim@testit.works> wrote:
>>>>>>>> 
>>>>>>>> 
>>>>>>>> Hi Marcus - I can put an image somewhere if that helps (do you just 
>>>>>>>> need the .image and .changes)?
>>>>>>>> 
>>>>>>>> Or you can repro from a fresh 6.1 if you follow the exercism Pharo 
>>>>>>>> instructions (https://exercism.io/tracks/pharo) to load the first 
>>>>>>>> hello world-world example and run the tests. This has my code changes 
>>>>>>>> to make create work with a nil class - but maybe we can do better?
>>>>>>> I will do that and have a look!
>>>>>>> 
>>>>>>>> Tim
>>>>>>>> 
>>>>>>>> 
>>>>>>>> Sent from my iPhone
>>>>>>>> 
>>>>>>>>> On 17 Aug 2018, at 06:21, Marcus Denker <marcus.den...@inria.fr> 
>>>>>>>>> wrote:
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>>> On 10 Aug 2018, at 23:16, Tim Mackinnon <tim@testit.works> wrote:
>>>>>>>>>> 
>>>>>>>>>> Actually I think I figured that bit out - a bit clumsily - (pointers 
>>>>>>>>>> appreciated)
>>>>>>>>>> 
>>>>>>>>>> createMissingClassActionFor: aMessage in: aContext
>>>>>>>>>> |errorNode senderContext newClass variableNode |
>>>>>>>>>> senderContext := aContext sender.
>>>>>>>>>> errorNode := senderContext method sourceNodeExecutedForPC: 
>>>>>>>>>> senderContext pc. 
>>>>>>>>>> variableNode := errorNode receiver receiver.
>>>>>>>>>> 
>>>>>>>>>> newClass := OCUndeclaredVariableWarning new node: variableNode; 
>>>>>>>>>> defineClass: variableNode name.
>>>>>>>>>> aContext restart.
>>>>>>>>>> 
>>>>>>>>>> However that last line is wrong, as it doesn’t restart with my newly 
>>>>>>>>>> defined class - I also tried
>>>>>>>>>> 
>>>>>>>>>> aContext restartWithNewReceiver: newClass
>>>>>>>>>> 
>>>>>>>>>> But again, I get a debugger where my class is still bound to nil. So 
>>>>>>>>>> what’s the trick to re-evaluate with the new class I’ve created? Or 
>>>>>>>>>> maybe I’m totally on the wrong track (still its very interesting…)
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> what is a bit bad is that you catch the problem “too late” (that is, 
>>>>>>>>> the DNU to nil, not the read of nil), so nil is already pushed on the 
>>>>>>>>> stack at this point.
>>>>>>>>> 
>>>>>>>>> I tried it in the inspector and at least the class binding was 
>>>>>>>>> correct after defining the class… do you have an image with the whole 
>>>>>>>>> code to try?
>>>>>>>>> 
>>>>>>>>> Marcus
>>> 
>>> 
>> 
>> 
> 
> 

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