Method Category Pane?
Stephane Ducasse
ducasse at iam.unibe.ch
Sun May 25 08:10:50 UTC 2003
On Sunday, May 25, 2003, at 08:26 AM, Joel Shellman wrote:
> Please excuse my newbie questions, I'm trying to read and get up to
> speed
> ASAP.
>
> I'm new to smalltalk and reading through:
>
> http://coweb.cc.gatech.edu:8888/squeakbook/uploads/noel.pdf
>
> and on page 12 it says the third pane in the System browser is the
> "method
> category pane". I thought that was the list of protocols. Are those
> synonymous?
Yes the third pane is just a list of folders (method categories or
protocols = same stuff)
to help you find your information.
>
> Also, it says that those categories are for human readability only,
> but I
> thought I read something that said that different objects/classes could
> support the same protocol. Ie. a Car could support the driveable
> protocol
> just as the Bicycle could.
Yes
> If I create a driveable protocol on Car and then
> use it on Bicycle, are those the same protocols, or are they
> different? ie.
> given the FAQ entry about finding all classes with a certain protocol:
>
> http://minnow.cc.gatech.edu/squeak/48
A protocol is just a set of message that an object can understand. So
if you
define the same message = method-***name*** then your objects
(instances of those class)
will be able to receive the same message.
For example we can open a window or open a file, the operations are
different but they have the same name.
This is what is named ad-hoc polymorphism because there is not too much
in common.
Now if you have a window and a colored window we can easily image that
there are a lot in common.
But the way have you got a look at the draft of the book for novices
I'm finishing
to write. http://scgwiki.iam.unibe.ch:8080/StephaneDucasseWiki
Contact me if you want to get more recent versions ;)
> That's just a string search that doesn't actually mean anything. In
> other
> words, two classes could be in the list returned from that call, but
> they
> could be completely unrelated. Is that correct?
>
> Thanks!
>
> -joel shellman
>
>
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