Support tags

[Anaminus]

Support tags

Tags should be supported somehow.

Considerations:

• We can have multiple DataModels.
• We want to scope by DataModel, or globally.
• Use descriptor extensions (#65) to configure the serialized property for tags?
  • The property used for tags can be changed on the fly. How would this interact with the tag database?
    • Treat configuration differently; to get tag support, config must be applied globally to all instances, and cannot be refined per instance.
    • Implement by only considering config of rbxmk.globalDesc?
• Instead, skip descriptor extensions. Use distinct API instead.
• For global database, use rbxmk.tags.
  • Value is a type that matches the CollectionService API without actually being an instance.
  • Can configure tag property (default "Tags").
    • Changing this does a complete database reevaluation.
  • Can configure class used for database scoped to DataModel (default "CollectionService").
    • What happens to existing instances of previous class? The additional behavior just drops. Would have to be implemented as a condition.
  • Can produce variation that scopes each method to a particular instance. This considers only the instance and its descendants.
• For DataModel-scoped database, match CollectionService API?
  • Would be union of Instance and above tags type.
  • Would be accessed via CollectionService instance under game. Class can be configured.
  • To support on the fly configuration of the class, this is implemented as a condition, similar to how GetService works for DataModel.
  • Selects scope by getting parent DataModel.

Tags API

• Type name?
  • Tags
  • TagCollection
  • TagDatabase
• Tags:WithScope(scope: Instance?): Tags
  • Return Tags that limits database to tree of scope.
  • Can scope out as well as in.
  • If scope is nil, scope is global.
  • Support multiple scopes? result is a union of each scope.
  • Ideally does not require any setup. Should be cheap to run.
• Tags:GetTagProperty(): string
  • Gets the name of the property used to serialize tags.
• Tags:SetTagProperty(name: string, transferMethod: Enum.TagTransferMethod = Move)
  • Sets the name of the property used to serialize tags.
  • transferMethod determines what to do with existing tag properties.
• Tags.ScopingClass: string?
  • Gets or sets the name of the class treated as CollectionService.
  • Can be set to nil to disable.
  • Initially set to "CollectionService".
• Reflected APIs:
  • Tags:AddTag(instance: Instance, tag: string)
    • Add tag to instance.
  • Tags:GetAllTags(): {string}
    • Get list of all tags.
  • Tags:GetTagged(tag: string): Objects
    • Get list of instances tagged with tag.
  • Tags:GetTags(instance: Instance): {string}
    • Get list of tags for instance.
  • Tags:HasTag(instance: Instance, tag: string): boolean
    • Return whether instance has tag.
  • Tags:RemoveTag(instance: Instance, tag: string)
    • Remove tag from instance.

Adds rbxmk.Enum.TagTransferMethod, which determines how SetTagProperty handles properties of the previous and next names:

Item	Value	Previous property	Next property
None	0	Untouched	Untouched
Copy	1	Untouched	Set from previous
Move	2	Removed	Set from previous