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

23 Feb 2015

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 &lt;btc(a)openinworld.com&gt; 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 &lt;jvdsandt(a)gmail.com&gt;
 wrote:

 On Mon, Feb 23, 2015 at 9:59 AM, Marcus Denker &lt;marcus.denker(a)inria.fr&gt;
 wrote:

  On 21 Feb 2015, at 21:11, Jan van de Sandt
&lt;jvdsandt(a)gmail.com&gt; 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