Roelof Wobben wrote:
If I understood everything well on page 26 my initialize methods must
look like this:
Cell >> initialize
super initialize.
self initializeActiveSegments.
self initializeExitSides.
self leanleft.
BlankCell >> initialize
super initialize.
self initializeExitSides.
MirrorCell >> initialize
super initialize
self leansLeft: true
Why then I see a message that #leanleft is not Understood in Blankcell.
or do I misunderstood that page. I find it a very confusing page.
Roelof
I've updated your example using the # and >> convention to describe
methods and the classes they belong to.
So the MNU (Message Not Understood) indicates that BlankCell doesn't
know how to #leanLeft
Now the first question you should ask yourself is "Does BlankCell or one
of its superclasses define #leftLeft ?"
Or the same question in another form "Which classes is #leanLeft defined
on?"
Note that the #leanleft is distinct from #leanLeft.
------------------------complete above before continuing
Your next question is "what is causing #leanLeft" to be called on a
BlankCell?"
Now to simply things I presume evaluating the following in Workspace
creates the same error...
BlankCell new <doIt>
So what you want to do is
BlankCell new <debugIt>
and trace through until you find where #leanLeft is about to be
executed. Pay attention in the call stack to when BlankCell>>initialize
transitions to Cell>initialize.
------------------------complete above before continuing
Now when debugging "BlankCell new" traces into Cell >> initialize, note
that "self leanLeft" refers send the message #leanLeft to the BlankCell
object, which then checks to see if BlankCell>>leanLeft is defined, and
then looks in the superclass to see if Cell>>leanLeft is defined, and
the looks in the next superclass to see if Object>>leanLeft is defined -
and if a definition is not found then BlankCell has a MNU.
So... I think your Cell>>initialize is incorrect. It would be useful to
know in more detail what makes you think it should look like that - to
deconstruct your confusion. Cell was only introduced on page 35, and its
initialize method looked like this
Cell>>initialize
super initialize.
self initializeActiveSegments.
I see nothing else on page 25 or 26 that indicates any further change to
Cell>>initialize.
The only thing I can guess at it that you've confused the bottom right
snapshot as applying to Cell when I guess it applies only to MirrorCell.
cheers -ben
