[OASIS Issue Tracker] Commented: (TOSCA-43) Type versioning

[ http://tools.oasis-open.org/issues/browse/TOSCA-43?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=30957#action_30957 ] 

Derek Palma commented on TOSCA-43:
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In the Aug 9th meeting I pointed out that Since TOSCA uses a type system, the only way to create new types are to derive from an existing type or create a new type, which makes type versioning a monomer. The appropriate solution is to express types using best practices in encoding type systems in XML documents.

> Type versioning
> ---------------
>
>                 Key: TOSCA-43
>                 URL: http://tools.oasis-open.org/issues/browse/TOSCA-43
>             Project: OASIS Topology and Orchestration Specification for Cloud Applications (TOSCA) TC
>          Issue Type: Sub-task
>          Components: Spec
>    Affects Versions: CSD04
>            Reporter: Derek Palma
>            Assignee: Derek Palma
>             Fix For: CSD04
>
>
> Type versioning. A more general term is schema or type evolution. This idea would be applicable if a type A exists, and someone later wants to create a type A' which is intended to be like A but not A and not related in a typed manner . It is important to note that A' and A are completely different types with no way to reason the delta between them. If one wanted some type based on A, they'd create a subclass of A and specialize accordingly. The practical uses of schema versioning is usually to create a completely new set of types which offer a different set of semantics than the previous version, so this is more of a way of labeling schemas.

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