as a general principle do not use thisContext.
S. > On 20 Jun 2020, at 01:12, Russ Whaley <whaley.r...@gmail.com> wrote: > > Thank you both for your insights. I’ve done the newFor: style many times, but > where it falls short is when I read in a STON object. No worries, I was just > wondering if there was something cool like “what object am I sitting on?”... > I looked through Context and the client message will be helpful to me in > other areas. I’m always eager to learn. Thank you very much for being willing > to teach. > > Thanks! > Russ > > On Wed, Jun 17, 2020 at 9:05 PM Richard O'Keefe <rao...@gmail.com > <mailto:rao...@gmail.com>> wrote: > I have a strong dislike for incompletely initialised objects. > So I would do it like this: > > myInstVar := TheDependentClass newFor: self. > > (together with any other essential information as parameters). > In my Smalltalk system it would look like this: > > Whatever subclass: #TheDependentClass > instanceConstantNames: 'owner' > ... > class methods for: 'instance creation' > newFor: owner > ^(self basicNew) pvtOwner: owner; yourself > > methods for: 'initialising' > pvtOwner: anObject > super pvtPostNew. > owner := anObject. > > Private access to methods with a 'pvt' prefix is enforced. > Instance constants can only be set in private methods. > There's an additional wrinkle that makes it a run time > error to call TheDependentClass new, so that you cannot get > an incompletely initialised object. > > In any Smalltalk you can follow similar conventions even if > they are not enforced. > > Of course if you don't mind incompletely initialised objects, > nothing stops you writing code that allows them. The question > is whether you want to be able to trust the 'owner' field or > not. > > On Thu, 18 Jun 2020 at 09:46, Esteban Maringolo <emaring...@gmail.com > <mailto:emaring...@gmail.com>> wrote: > Objects interact with each other by sending messages, although you can > get the sender by using reflection (thisContext sender), it is not a > common practice to do so. > So if you need another object to know the sender (or any other object) > you simply pass it as a parameter. > > So modifying your example, and making the syntax actually work it would be: > > self property: ObjectClass new. > self property caller: self. > > and then when you need to deal with that you can simply get a > reference to that object and send it a message to do something: > self property caller doSomething. > > You can also have something like > > self property: (ObjectClass for: self) > > > In that case the #for: message is received by "ObjectClass class", > which you can think of as if it were a Factory or a "static" method > (it is not! it is much more powerful than that). > > ObjectClass class>>#for: callerObject > ^self new > setCaller: callerObject; > yourself > > And that's it, you have an instance of ObjectClass that you > initialized by sending #for: instead of #new (internally it ended up > calling #new, but from the outside it was just a message send). > > And for the most part that's Smalltalk: Objects and messages. > > Regards! > > Esteban A. Maringolo > > On Wed, Jun 17, 2020 at 6:19 PM Russ Whaley <whaley.r...@gmail.com > <mailto:whaley.r...@gmail.com>> wrote: > > > > I find myself, over and over, creating a & storing q new object in an > > instVar, then storing (my)self on that object - so I can have easy access > > to the 'object that created me.' > > > > <what I do now...> > > > > self instVar := NewClass new. > > > > self instVar callingObject: self. > > > > "where these call the same messages" > > > > self myMessage. > > > > self instVar callingObject myMessage. > > > > <is there a way to...> > > > > self instVar := NewClass new. > > > > self instVar objectWhoCreatedMe myMessage. > > > > "I know there is a 'thisContext sender' - but is there a 'who created me' > > concept?" > > > > > > Ultimately, there is no real overhead to storing (my)self on a new object, > > I guess, but as I'm developing and testing, I tend to have a whole lot of > > 'stranded objects' I have to remove manually. > > > > Thoughts? > > > > Thanks! > > -- > > Russ Whaley > > whaley.r...@gmail.com <mailto:whaley.r...@gmail.com> > > -- > Russ Whaley > whaley.r...@gmail.com <mailto:whaley.r...@gmail.com> -------------------------------------------- Stéphane Ducasse http://stephane.ducasse.free.fr / http://www.pharo.org 03 59 35 87 52 Assistant: Aurore Dalle FAX 03 59 57 78 50 TEL 03 59 35 86 16 S. Ducasse - Inria 40, avenue Halley, Parc Scientifique de la Haute Borne, Bât.A, Park Plaza Villeneuve d'Ascq 59650 France
