Re: [Pharo-dev] Example implementation of associations with Slots in Pharo 4.0

[stepharo]

we should ask a modeling expert. We have one in the team.


Le 4/3/15 06:20, Ben Coman a écrit :
Could someone explain why the "ToOne" and "ToMany" are the preferred 
semantics for the class names versus OneRelatedTo or RelatedToOne ?

To me, "ToOne" feels like its describing the #directedMovies part.
I guess it makes sense if you are looking in towards #director.
cheers -ben

On Fri, Feb 27, 2015 at 7:51 PM, Marcus Denker > wrote:



> On 27 Feb 2015, at 11:46, Jan van de Sandt mailto:jvdsa...@gmail.com>> wrote:
>
> Hello,
>
> Thanks for your suggestions. I have improved the naming and
definition to this:
>
> Object subclass: #SlotExampleMovie
>   slots: {
>   #name.
>   #year.
>   #director => ToOneRelationSlot inverse:
#directedMovies inClass: #SlotExamplePerson.
>   #actors => ToManyRelationSlot inverse:
#actedInMovies inClass: #SlotExamplePerson }
>   classVariables: {  }
>   category: 'SlotAssociations-Tests-Example'
>
> Because it is for now just an example I haven't renamed the Slot
classes yet.
>

Thanks! I will add the associations as examples to Pharo4 (today I
think)

Marcus

Re: [Pharo-dev] Example implementation of associations with Slots in Pharo 4.0

[Marcus Denker]

> On 27 Feb 2015, at 12:51, Marcus Denker  wrote:
> 
> 
>> On 27 Feb 2015, at 11:46, Jan van de Sandt  wrote:
>> 
>> Hello,
>> 
>> Thanks for your suggestions. I have improved the naming and definition to 
>> this:
>> 
>> Object subclass: #SlotExampleMovie
>>  slots: { 
>>  #name.
>>  #year. 
>>  #director => ToOneRelationSlot inverse: #directedMovies 
>> inClass: #SlotExamplePerson. 
>>  #actors => ToManyRelationSlot inverse: #actedInMovies inClass: 
>> #SlotExamplePerson }
>>  classVariables: {  }
>>  category: 'SlotAssociations-Tests-Example'
>> 
>> Because it is for now just an example I haven't renamed the Slot classes yet.
>> 
> 
> Thanks! I will add the associations as examples to Pharo4 (today I think)
> 

It took a bit longer as loading the examples revealed a bug, but now they are 
in 
Pharo4 update #534.

Marcus

Re: [Pharo-dev] Example implementation of associations with Slots in Pharo 4.0

[Marcus Denker]

> On 04 Mar 2015, at 06:20, Ben Coman  wrote:
> 
> Could someone explain why the "ToOne" and "ToMany" are the preferred 
> semantics for the class names versus OneRelatedTo or RelatedToOne ?
> To me, "ToOne" feels like its describing the #directedMovies part.
> I guess it makes sense if you are looking in towards #director. 
> cheers -ben 
> 

Right now I care more about fixing all bugs to make the examples actually 
loadable…
there are so many details… e.g. integrating the examples broke the build as the 
code that
generates the #initialize method asked for initials… 

> On Fri, Feb 27, 2015 at 7:51 PM, Marcus Denker  > wrote:
> 
> > On 27 Feb 2015, at 11:46, Jan van de Sandt  > > wrote:
> >
> > Hello,
> >
> > Thanks for your suggestions. I have improved the naming and definition to 
> > this:
> >
> > Object subclass: #SlotExampleMovie
> >   slots: {
> >   #name.
> >   #year.
> >   #director => ToOneRelationSlot inverse: #directedMovies 
> > inClass: #SlotExamplePerson.
> >   #actors => ToManyRelationSlot inverse: #actedInMovies 
> > inClass: #SlotExamplePerson }
> >   classVariables: {  }
> >   category: 'SlotAssociations-Tests-Example'
> >
> > Because it is for now just an example I haven't renamed the Slot classes 
> > yet.
> >
> 
> Thanks! I will add the associations as examples to Pharo4 (today I think)
> 
> Marcus
> 
> 
> 

Re: [Pharo-dev] Example implementation of associations with Slots in Pharo 4.0

[Ben Coman]

Could someone explain why the "ToOne" and "ToMany" are the preferred
semantics for the class names versus OneRelatedTo or RelatedToOne ?
To me, "ToOne" feels like its describing the #directedMovies part.
I guess it makes sense if you are looking in towards #director.
cheers -ben

On Fri, Feb 27, 2015 at 7:51 PM, Marcus Denker 
wrote:

>
> > On 27 Feb 2015, at 11:46, Jan van de Sandt  wrote:
> >
> > Hello,
> >
> > Thanks for your suggestions. I have improved the naming and definition
> to this:
> >
> > Object subclass: #SlotExampleMovie
> >   slots: {
> >   #name.
> >   #year.
> >   #director => ToOneRelationSlot inverse: #directedMovies
> inClass: #SlotExamplePerson.
> >   #actors => ToManyRelationSlot inverse: #actedInMovies
> inClass: #SlotExamplePerson }
> >   classVariables: {  }
> >   category: 'SlotAssociations-Tests-Example'
> >
> > Because it is for now just an example I haven't renamed the Slot classes
> yet.
> >
>
> Thanks! I will add the associations as examples to Pharo4 (today I think)
>
> Marcus
>
>
>

Re: [Pharo-dev] Example implementation of associations with Slots in Pharo 4.0

[Marcus Denker]

> On 27 Feb 2015, at 11:46, Jan van de Sandt  wrote:
> 
> Hello,
> 
> Thanks for your suggestions. I have improved the naming and definition to 
> this:
> 
> Object subclass: #SlotExampleMovie
>   slots: { 
>   #name.
>   #year. 
>   #director => ToOneRelationSlot inverse: #directedMovies 
> inClass: #SlotExamplePerson. 
>   #actors => ToManyRelationSlot inverse: #actedInMovies inClass: 
> #SlotExamplePerson }
>   classVariables: {  }
>   category: 'SlotAssociations-Tests-Example'
> 
> Because it is for now just an example I haven't renamed the Slot classes yet.
> 

Thanks! I will add the associations as examples to Pharo4 (today I think)

Marcus

Re: [Pharo-dev] Example implementation of associations with Slots in Pharo 4.0

[Jan van de Sandt]

Hello,

Thanks for your suggestions. I have improved the naming and definition to
this:

Object subclass: #SlotExampleMovie
slots: {
#name.
#year.
#director => ToOneRelationSlot inverse: #directedMovies inClass:
#SlotExamplePerson.
#actors => ToManyRelationSlot inverse: #actedInMovies inClass:
#SlotExamplePerson }
classVariables: {  }
category: 'SlotAssociations-Tests-Example'

Because it is for now just an example I haven't renamed the Slot classes
yet.

Jan.




On Tue, Feb 24, 2015 at 8:03 AM, Marcus Denker 
wrote:

>
> On 23 Feb 2015, at 22:34, Ben Coman  wrote:
>
> I haven't played with the relation example yet, but will real soon.  Just
> some initial thoughts...
>
> I like RelationSlot.  To me association seems one-way while a relation is
> two-way.
>
> btw, Is there some reason to not match the syntax of the often cited paper
> "Flexible Object Layout" ?
> I see one advantage is that its easier to read all the slot names
> vertically aligned.
>
> Object subclass: #SlotExampleMovie
> slots: {
> #name.
> #year.
> #director => ToOneRelationSlot opposite: #directedMovies class:
> #SlotExamplePerson.
> #actors => ToManyRelationSlot opposite: #actedInMovies  class: 
> #SlotExamplePerson.
> }
> classVariables: {  }
> category: 'SlotAssociations-Tests-Example'
>
>
> Also maybe an alternative slot class name so that it reads more like a
> sentence... "#director related to one #directedMovies in class
> #SlotExamplePerson"
>
> Object subclass: #SlotExampleMovie
> slots: {
> #name.
> #year.
> #director => RelatedToOne inverse: #directedMovies inClass:
> #SlotExamplePerson.
> #actors => RelatedToMany inverse: #actedInMovies  inClass: #SlotExamplePerson.
> }
> classVariables: {  }
> category: 'SlotAssociations-Tests-Example'
>
>
> Something like those would be good… yes, I think having the slot name in
> front is important.
>
> Marcus
>
>

Re: [Pharo-dev] Example implementation of associations with Slots in Pharo 4.0

[Marcus Denker]

> On 23 Feb 2015, at 22:34, Ben Coman  wrote:
> 
> I haven't played with the relation example yet, but will real soon.  Just 
> some initial thoughts...
> 
> I like RelationSlot.  To me association seems one-way while a relation is 
> two-way.
> 
> btw, Is there some reason to not match the syntax of the often cited paper 
> "Flexible Object Layout" ?  
> I see one advantage is that its easier to read all the slot names vertically 
> aligned.
> 
> Object subclass: #SlotExampleMovie
>   slots: { 
>   #name. 
>   #year. 
>   #director => ToOneRelationSlot opposite: #directedMovies class: 
> #SlotExamplePerson.
>   #actors => ToManyRelationSlot opposite: #actedInMovies  class: 
> #SlotExamplePerson. }
>   classVariables: {  }
>   category: 'SlotAssociations-Tests-Example'
> 
> 
> Also maybe an alternative slot class name so that it reads more like a 
> sentence... "#director related to one #directedMovies in class 
> #SlotExamplePerson"
> 
> Object subclass: #SlotExampleMovie
>   slots: { 
>   #name. 
>   #year. 
>   #director => RelatedToOne inverse: #directedMovies inClass: 
> #SlotExamplePerson.
>   #actors => RelatedToMany inverse: #actedInMovies  inClass: 
> #SlotExamplePerson. }
>   classVariables: {  }
>   category: 'SlotAssociations-Tests-Example'
> 

Something like those would be good… yes, I think having the slot name in front 
is important.

Marcus

Re: [Pharo-dev] Example implementation of associations with Slots in Pharo 4.0

[Marcus Denker]

> On 23 Feb 2015, at 19:33, Jan van de Sandt  wrote:
> 
> 
> On Mon, Feb 23, 2015 at 9:59 AM, Marcus Denker  > wrote:
> 
> > On 21 Feb 2015, at 21:11, Jan van de Sandt  > > wrote:
> >
> > Today I experimented a little with the new Slots feature of Pharo 4.0. As 
> > an example I implemented support for associations/relationships.
> >
> 
> Very nice! Can I add this to Pharo4 as an example?
> 
> Sure, cool!
>  

Ok, I will do that.

Marcus

Re: [Pharo-dev] Example implementation of associations with Slots in Pharo 4.0

[Tudor Girba]

Exactly :).

In Fame, there is a FMMultivalueLink hierarchy that implement many to one
and many to many relations. This implementation exists since before slots
and now we should reimplement them with slots. It will make the code so
much nicer :).

Anyone interested in picking this up?

Cheers,
Doru


On Mon, Feb 23, 2015 at 10:34 PM, Ben Coman  wrote:

> I haven't played with the relation example yet, but will real soon.  Just
> some initial thoughts...
>
> I like RelationSlot.  To me association seems one-way while a relation is
> two-way.
>
> btw, Is there some reason to not match the syntax of the often cited paper
> "Flexible Object Layout" ?
> I see one advantage is that its easier to read all the slot names
> vertically aligned.
>
> Object subclass: #SlotExampleMovie
> slots: {
> #name.
> #year.
> #director => ToOneRelationSlot opposite: #directedMovies class:
> #SlotExamplePerson.
> #actors => ToManyRelationSlot opposite: #actedInMovies  class: 
> #SlotExamplePerson.
> }
> classVariables: {  }
> category: 'SlotAssociations-Tests-Example'
>
>
> Also maybe an alternative slot class name so that it reads more like a
> sentence... "#director related to one #directedMovies in class
> #SlotExamplePerson"
>
> Object subclass: #SlotExampleMovie
> slots: {
> #name.
> #year.
> #director => RelatedToOne inverse: #directedMovies inClass:
> #SlotExamplePerson.
> #actors => RelatedToMany inverse: #actedInMovies  inClass: #SlotExamplePerson.
> }
> classVariables: {  }
> category: 'SlotAssociations-Tests-Example'
>
> Or even...
>
> Object subclass: #SlotExampleMovie
> slots: {
> #name.
> #year.
> #director => OneRelatedTo many: #directedMovies inClass:
> #SlotExamplePerson.
> #actors => ManyRelatedTo many: #actedInMovies  inClass: #SlotExamplePerson.
> }
> classVariables: {  }
> category: 'SlotAssociations-Tests-Example'
>
> cheers -ben
>
>
> On Tue, Feb 24, 2015 at 2:33 AM, Jan van de Sandt 
> wrote:
>
>>
>> On Mon, Feb 23, 2015 at 9:59 AM, Marcus Denker 
>> wrote:
>>
>>>
>>> > On 21 Feb 2015, at 21:11, Jan van de Sandt  wrote:
>>> >
>>> > Today I experimented a little with the new Slots feature of Pharo 4.0.
>>> As an example I implemented support for associations/relationships.
>>> >
>>>
>>> Very nice! Can I add this to Pharo4 as an example?
>>>
>>> Sure, cool!
>>
>>
>>> My idea is that at first we add these things as examples, and then later
>>> take the examples and distill a library of
>>> generally useful slots.
>>>
>>>
>>>
>> That sounds like a good approach to get familiar with these kind of new
>> features.
>>
>> Some things I can do to improve the Example
>> -  Add an option to make one side of the association readonly. In most
>> situations I think it's a good idea to update an association only from one
>> side to keep things simple.
>> - Whats a better name AssociationSlot or RelationSlot? I'm not sure
>> - As Stéphane said, isn't there a nicer way to declare the associations?
>> - Better error handling
>>
>> Jan.
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>


-- 
www.tudorgirba.com

"Every thing has its own flow"

Re: [Pharo-dev] Example implementation of associations with Slots in Pharo 4.0

[Ben Coman]

I haven't played with the relation example yet, but will real soon.  Just
some initial thoughts...

I like RelationSlot.  To me association seems one-way while a relation is
two-way.

btw, Is there some reason to not match the syntax of the often cited paper
"Flexible Object Layout" ?
I see one advantage is that its easier to read all the slot names
vertically aligned.

Object subclass: #SlotExampleMovie
slots: {
#name.
#year.
#director => ToOneRelationSlot opposite: #directedMovies class:
#SlotExamplePerson.
#actors => ToManyRelationSlot opposite: #actedInMovies  class:
#SlotExamplePerson.
}
classVariables: {  }
category: 'SlotAssociations-Tests-Example'


Also maybe an alternative slot class name so that it reads more like a
sentence... "#director related to one #directedMovies in class
#SlotExamplePerson"

Object subclass: #SlotExampleMovie
slots: {
#name.
#year.
#director => RelatedToOne inverse: #directedMovies inClass:
#SlotExamplePerson.
#actors => RelatedToMany inverse: #actedInMovies  inClass: #SlotExamplePerson.
}
classVariables: {  }
category: 'SlotAssociations-Tests-Example'

Or even...

Object subclass: #SlotExampleMovie
slots: {
#name.
#year.
#director => OneRelatedTo many: #directedMovies inClass: #SlotExamplePerson.
#actors => ManyRelatedTo many: #actedInMovies  inClass: #SlotExamplePerson.
}
classVariables: {  }
category: 'SlotAssociations-Tests-Example'

cheers -ben


On Tue, Feb 24, 2015 at 2:33 AM, Jan van de Sandt 
wrote:

>
> On Mon, Feb 23, 2015 at 9:59 AM, Marcus Denker 
> wrote:
>
>>
>> > On 21 Feb 2015, at 21:11, Jan van de Sandt  wrote:
>> >
>> > Today I experimented a little with the new Slots feature of Pharo 4.0.
>> As an example I implemented support for associations/relationships.
>> >
>>
>> Very nice! Can I add this to Pharo4 as an example?
>>
>> Sure, cool!
>
>
>> My idea is that at first we add these things as examples, and then later
>> take the examples and distill a library of
>> generally useful slots.
>>
>>
>>
> That sounds like a good approach to get familiar with these kind of new
> features.
>
> Some things I can do to improve the Example
> -  Add an option to make one side of the association readonly. In most
> situations I think it's a good idea to update an association only from one
> side to keep things simple.
> - Whats a better name AssociationSlot or RelationSlot? I'm not sure
> - As Stéphane said, isn't there a nicer way to declare the associations?
> - Better error handling
>
> Jan.
>
>
>
>
>
>
>
>
>
>
>
>

Re: [Pharo-dev] Example implementation of associations with Slots in Pharo 4.0

[Marcus Denker]

> On 21 Feb 2015, at 21:11, Jan van de Sandt  wrote:
> 
> Today I experimented a little with the new Slots feature of Pharo 4.0. As an 
> example I implemented support for associations/relationships. 
> 

Very nice! Can I add this to Pharo4 as an example?

My idea is that at first we add these things as examples, and then later take 
the examples and distill a library of 
generally useful slots.

Marcus

Re: [Pharo-dev] Example implementation of associations with Slots in Pharo 4.0

[stepharo]

Hi Jan

Excellent! We know exactly whay we want slots and this is exactly for 
such kind of extensions.


you may want to read the paper of Kasper Osterbye 
http://itu.dk/people/kasper/cv.htm
R.11  Kasper Østerbye. Associations as a Language Construct. In 
Proceedings of TOOLS 29, Ed. Richard Michel et.al., Nancy, June 7-10 
1999. Page 224-235. (pdf)


I would love to have a nice package with such relationships because we 
used them all the time.

I will blog about your nice experience.

We should probably find a nicer way to declare them.
Stef


Le 21/2/15 21:11, Jan van de Sandt a écrit :
Today I experimented a little with the new Slots feature of Pharo 4.0. 
As an example I implemented support for associations/relationships.


With it you can link two slots together so an update on one side will 
also update the other side of the association/relationship.


I used these Movie and Person classes for testing:

Object subclass: #SlotExampleMovie
slots: {
#name.
#year.
ToOneAssociationSlot named: #director target: #SlotExamplePerson 
inverse: #directedMovies.
ToManyAssociationSlot named: #actors target: #SlotExamplePerson 
inverse: #actedInMovies }

classVariables: {  }
category: 'SlotAssociations-Tests-Example'
Object subclass: #SlotExamplePerson
slots: {
#name.
ToManyAssociationSlot named: #directedMovies target: #SlotExampleMovie 
inverse: #director.
ToManyAssociationSlot named: #actedInMovies target: #SlotExampleMovie 
inverse: #actors }

classVariables: {  }
category: 'SlotAssociations-Tests-Example'

With this definition the director of a Movie must be a Persion 
instance. When you set the director of a movie this movie is 
automatically added to the directedMovies collection of that person. 
Off course it also works the other way around.


It took very little code to add these association slots. I think Slots 
are a really nice addition to Pharo! If anyone wants to have a look at 
the code:


MCHttpRepository
location: 'http://smalltalkhub.com/mc/JanVanDeSandt/Stuff/main'
user: ''
password: ''

Jan.

[Pharo-dev] Example implementation of associations with Slots in Pharo 4.0

[Jan van de Sandt]

Today I experimented a little with the new Slots feature of Pharo 4.0. As
an example I implemented support for associations/relationships.

With it you can link two slots together so an update on one side will also
update the other side of the association/relationship.

I used these Movie and Person classes for testing:

Object subclass: #SlotExampleMovie
slots: {
#name.
#year.
ToOneAssociationSlot named: #director target: #SlotExamplePerson inverse:
#directedMovies.
ToManyAssociationSlot named: #actors target: #SlotExamplePerson inverse:
#actedInMovies }
classVariables: {  }
category: 'SlotAssociations-Tests-Example'
Object subclass: #SlotExamplePerson
slots: {
#name.
ToManyAssociationSlot named: #directedMovies target: #SlotExampleMovie
inverse: #director.
ToManyAssociationSlot named: #actedInMovies target: #SlotExampleMovie
inverse: #actors }
classVariables: {  }
category: 'SlotAssociations-Tests-Example'

With this definition the director of a Movie must be a Persion instance.
When you set the director of a movie this movie is automatically added to
the directedMovies collection of that person. Off course it also works the
other way around.

It took very little code to add these association slots. I think Slots are
a really nice addition to Pharo! If anyone wants to have a look at the code:

MCHttpRepository
location: 'http://smalltalkhub.com/mc/JanVanDeSandt/Stuff/main'
user: ''
password: ''

Jan.