Please reply under posts. It makes things less confusing.<br><br><div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div>
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On Jun 29, 2009, at 3:43 PM, David Goehrig wrote:<br>
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<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
What I typically what I've been doing to eliminate all of these methods with a single simple change:<br>
<br>
Object<br>
doesNoUnderstand: aMessage<br>
^ false<br>
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</div></div></blockquote><div> </div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div><div class="h5">On Tue, Jun 30, 2009 at 3:26 PM, Cameron Sanders <span dir="ltr"><<a href="mailto:csanders.personal@functional-analyst.com">csanders.personal@functional-analyst.com</a>></span> wrote:<br>
What you write (down below) is close to what I was thinking when I said have all #isXXX return false by default;<br>
although I would test that the first two characters match 'i' and 's'
and that more characters exist, if so, return false, otherwise, normal
#doesNotUnderstand: behavior.<br>
<br>
I would treat #is by itself differently... it is ... or it couldn't be
tested! So I would do nothing for simple #is. and I don't like #is:
because it looks like a class type test... but that is part of the
point, eh?<br>
<br>
I'll have to go back to the original example (by <a href="mailto:siguctua@gmail.com" target="_blank">siguctua@gmail.com</a>,
and read more about lambdas) but I thought that CVLambda would
implement #isCVLambda to return true when it can be verified to be
one. The example did not illustrate #doesNotUnderstand:.<br>
<br>
Back to the question of adding behavior to classes that you don't own.
VisualWorks has a means to extend a class in a different package ... as
I recall. As I recall, squeak has no such capability, right?<br>
<br>
</div></div></blockquote></div><br>Squeak certainly has that capability, but I would discourage you from using it.<br clear="all"><br>Changing the implementation of doesNotUnderstand: is a code smell. You're starting to play with voodoo and you need a *very* good reason to do it. Otherwise you'll have made yourself a very difficult application to debug.<br>
<br>In my opinion (which doubtless isn't shared by everyone here), base classes such as Object should not have a lot of >>isXXX methods. >>isBoolean and >>isString are okay (although I never use them), but >>isMorph or >>isColor or anything not related to the Kernel classes are pollution.<br>
<br>If you're using an >>isXXX method, then your code probably needs refactoring. It means you're implementing class specific behaviour using conditional >>ifTrue: blocks. Typically, your code will be working with subclasses of a specific class, and you'd invoke polymorphic methods to get class specific behaviour rather than using conditional blocks such as >>ifTrue:, >>ifFalse: etc.<br>
<br>If your code really does handle an object of any possible class (which is rare but does occur), then you can use >>isKindOf:, >>isMemberOf: and >>respondsTo:. <br><br>Igor's lambda example was a bit complex for me to work through so I can't really comment on it.<br>
<br>Gulik.<br><br>-- <br><a href="http://gulik.pbwiki.com/">http://gulik.pbwiki.com/</a><br>