[Moose-dev] Re: is there a repository for the metamodel that are loadedin Moose

On 18 Jul 2007, at 11:17 , Stéphane Ducasse wrote: To answer that, we have to distinguish between Meta and Moose. You can load multiple Metamodels in Meta, but alas, not in Moose. Let me elaborate that a bit more: -------- Meta Meta.System is a container for one set of Model, MModel and MMModel. There can be as many System instances as you want, and they may share all the same MMModel. Similar to a singelton, one selected system is always the current reference system System reference which can be changed using a context oriented scheme mySystem scopeWhile: [ .... ] which will make mySystem the reference system within the context of that block. Let's assume that you want to load two MModels, Famix and Mushroom, sharing the same MMModel | famix mushroom | famix := System withEMOF. mushroom := famix withSameMetaMetamodel. famix scopeWhile: [ "...load Famix metamodel here..." ]. mushroom scopeWhile: [ "...load Mushroom metamodel here..." ]. and then you can access for example Mushroom's elements either direct mushroom metamodel elements or using the context oriented way mushroom scopeWhile: [ System reference metamodel elements ] the you can do the same for models, having multiple mushroom models | mario luigi | mario := mushroom withSameMetamodel. luigi := mushroom withSameMetamodel. mario scopeWhile: [ "... load a Mushroom model ..." ]. luigi scopeWhile: [ "... load another Mushroom model ...' ]. and again you can access elements direct or via context mario elements. mario scopeWhile: [ System reference model elements ]. --------- Moose Alas, Moose does not use multiple System instances for multiple Models or MModels. Moose does everything using the default reference system. Hence all metamodels that you load into Moose are merged into M2 layer of the default reference system! In other words, you can not load Metamodels into Moose, you can only extend Moose's default Metamodel with your custom elements. By the way, for the models, Moose doesn't even use the default reference system, but manages its "models" somewhere outside in custom data containers not related to Meta. cheers, AA