Help! initialize event
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Hello All
I'm trying to work thru. the Dolphin Companion book. I have created the Animal Class and set the getter-setter methods for name, foundationYear instance variables. In the class, I add the initialise method as initialize (self new) foundationYear:0; name:String new. But when I inspect an := Animal new, I see that the vars are not initialized. This may be stupid, but any ideas what I'm doing wrong here. thanks Sunit [hidden email] |
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Sunit
In my experience, when deriving a class from Object directly, one has to override the class method new if one wants to automatically call the initialize method. For example: Animal>>new ^super new initialize. The initialize instance method would then look like: Animal>>initialize self foundationYear: 0; name: String new. The instance method initialize should not call new, rather the other way around. The class method new calls the instance method initialize, which should then create the required instance variables. Hope that helps, Jon "Sunit Joshi" <[hidden email]> wrote in message news:[hidden email]... > Hello All > I'm trying to work thru. the Dolphin Companion book. I have created > the Animal Class and set the getter-setter methods for name, > foundationYear instance variables. > In the class, I add the initialise method as > initialize > (self new) foundationYear:0; name:String new. > > But when I inspect an := Animal new, I see that the vars are not > initialized. This may be stupid, but any ideas what I'm doing wrong > here. > > thanks > Sunit > [hidden email] |
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On Tue, 10 Sep 2002 15:44:28 GMT,
Jonathon Spaeth <[hidden email]> wrote: > Sunit > It just took me about five minutes to figure out that you are not talking about SUnit ... time for a nap, I guess. s. |
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In reply to this post by Jonathon Spaeth
Thanks for the info. I still get the same thing.
My new is now ^super new initialize and initialize class method now ^(self new) foundationYear:0; name:String new Since the vars are instance variables, I thought I should have the new message sent first to get the instance object. Sunit [hidden email] "Jonathon Spaeth" <[hidden email]> wrote in message news:<wrof9.612$[hidden email]>... > Sunit > > In my experience, when deriving a class from Object directly, one has to > override the class method new if one wants to automatically call the > initialize method. For example: > > Animal>>new > ^super new initialize. > > The initialize instance method would then look like: > > Animal>>initialize > self foundationYear: 0; > name: String new. > > The instance method initialize should not call new, rather the other way > around. The class method new calls the instance method initialize, which > should then create the required instance variables. > > Hope that helps, > Jon > > > "Sunit Joshi" <[hidden email]> wrote in message > news:[hidden email]... > > Hello All > > I'm trying to work thru. the Dolphin Companion book. I have created > > the Animal Class and set the getter-setter methods for name, > > foundationYear instance variables. > > In the class, I add the initialise method as > > initialize > > (self new) foundationYear:0; name:String new. > > > > But when I inspect an := Animal new, I see that the vars are not > > initialized. This may be stupid, but any ideas what I'm doing wrong > > here. > > > > thanks > > Sunit > > [hidden email] |
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It looks as if you're have the #initialize method on the class side. If you
do, that's the problem. Assuming I understand what you're trying to do, the class method #new should look like: new ^super new initialize The words "super new" create the new instance. The word "initialize" is a message sent to that instance, so the #initialize method needs to be on the instance side. Because it's for an instance that already exists, it should simply be: initialize self foundationYear: 0; name: String new Hope this helps, Don "Sunit Joshi" <[hidden email]> wrote in message news:[hidden email]... > Thanks for the info. I still get the same thing. > My new is now ^super new initialize > and initialize class method now > ^(self new) foundationYear:0; name:String new > > Since the vars are instance variables, I thought I should have the new > message sent first to get the instance object. > > Sunit > [hidden email] > > "Jonathon Spaeth" <[hidden email]> wrote in message > > Sunit > > > > In my experience, when deriving a class from Object directly, one has to > > override the class method new if one wants to automatically call the > > initialize method. For example: > > > > Animal>>new > > ^super new initialize. > > > > The initialize instance method would then look like: > > > > Animal>>initialize > > self foundationYear: 0; > > name: String new. > > > > The instance method initialize should not call new, rather the other way > > around. The class method new calls the instance method initialize, > > should then create the required instance variables. > > > > Hope that helps, > > Jon > > > > > > "Sunit Joshi" <[hidden email]> wrote in message > > news:[hidden email]... > > > Hello All > > > I'm trying to work thru. the Dolphin Companion book. I have created > > > the Animal Class and set the getter-setter methods for name, > > > foundationYear instance variables. > > > In the class, I add the initialise method as > > > initialize > > > (self new) foundationYear:0; name:String new. > > > > > > But when I inspect an := Animal new, I see that the vars are not > > > initialized. This may be stupid, but any ideas what I'm doing wrong > > > here. > > > > > > thanks > > > Sunit > > > [hidden email] |
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In reply to this post by Sunit Joshi
Sunit
The vars being instance variables, the initialize method should be an instance method, as well. Ocassionally, I see a class method named initialize which serves the same purpose for class variables. However in the statement: super new initialize. The initialize message is being sent to the newly-created instance, as an instance method. You're right that new should be sent before initialize, but the initialize method you should be writing is in the instance, not the class. Jon "Sunit Joshi" <[hidden email]> wrote in message news:[hidden email]... > Thanks for the info. I still get the same thing. > My new is now ^super new initialize > and initialize class method now > ^(self new) foundationYear:0; name:String new > > Since the vars are instance variables, I thought I should have the new > message sent first to get the instance object. > > Sunit > [hidden email] > > "Jonathon Spaeth" <[hidden email]> wrote in message > > Sunit > > > > In my experience, when deriving a class from Object directly, one has to > > override the class method new if one wants to automatically call the > > initialize method. For example: > > > > Animal>>new > > ^super new initialize. > > > > The initialize instance method would then look like: > > > > Animal>>initialize > > self foundationYear: 0; > > name: String new. > > > > The instance method initialize should not call new, rather the other way > > around. The class method new calls the instance method initialize, > > should then create the required instance variables. > > > > Hope that helps, > > Jon > > > > > > "Sunit Joshi" <[hidden email]> wrote in message > > news:[hidden email]... > > > Hello All > > > I'm trying to work thru. the Dolphin Companion book. I have created > > > the Animal Class and set the getter-setter methods for name, > > > foundationYear instance variables. > > > In the class, I add the initialise method as > > > initialize > > > (self new) foundationYear:0; name:String new. > > > > > > But when I inspect an := Animal new, I see that the vars are not > > > initialized. This may be stupid, but any ideas what I'm doing wrong > > > here. > > > > > > thanks > > > Sunit > > > [hidden email] |
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