syntactic sugar for association description in generator

[NicolasAnquetil]

just like #apply:on:oppositeTraits:on: for "reciprocal traits", there could be a generator method to simplify creating association between two classes

[NicolasAnquetil]

see moosetechnology/Moose#2070

[NicolasAnquetil]

may be a method like: #applyAssociation:fromSide:toSide: or withFrom:withTo: or fromRole:toRole: ...

[NicolasAnquetil]

Currently to create an association such as Invocation, we must:

• in #defineClasses
  • create a class #Invoked-name
  • create a class #Invoker-name
  • create a class #Invok-name
• in #defineHierarchy
  • Invoked class uses TInvocable
  • Invoker class uses TWithInvocations
  • Invok class uses TInvocation

Things happen in two methods (#defineClasses and #defineHierarchy), often lines are separated because the classes have other properties/inheritances, so the information is scattered which does not make clear the creation of a relationship.

Improvement initially wished was to create classes as usual and define the relationship (i.e. uses of traits) in #defineRelations:

apply: TInvocation on: Invok-class withFrom: Invoker-class withTo: Invoked-class

But we don't have identification of from/to slots in TInvocation so we cannot compute the trait needed by the from/to sides.

[NicolasAnquetil]

Two possible solutions:

• creating the classe in #defineClasses + a method with 6 parameters:

applyAssociation: TInvocation on: Invok-class fromSlot: #sender on: Invoker-class toSlot: #candidates on: Invoked-class

(sender is the from slot in TInvocation and candidates is the to slot)

• small variation: Invok class uses TInvocation (and no other!) in #defineHierarchy:

applyAssociation: Invok-class fromSlot: #sender on: Invoker-class toSlot: #candidates on: Invoked-class

• Introduce a special notation for association creation so that the to and from slots are explicitly meta-described. There is already FmxMBRelationSide>>source and FmxMBRelationSide>>target which could be some basis for this ...