# abstract types in archetypes

**Category:** [Technical (archive)](https://discourse.openehr.org/c/technical-archive/156)
**Created:** 2012-05-03 09:19 UTC
**Views:** 1
**Replies:** 2
**URL:** https://discourse.openehr.org/t/abstract-types-in-archetypes/15170

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## Post #1 by @system

Hi all,

Please allow me a short question\.

Is it allowed to define abstract types in archetypes,  I once saw an archetype which held an EVENT as attribute, so the constructor of the rm\-object which had to be validated against the archetype, could at runtime decide if he wanted to use a POINT\_EVENT or INTERVAL\_EVENT\.
Is this allowed?

Same can occur with data\_structures and data\_values\.

Suppose \(theoretically\) an archetype which has LOCATABLE as definition\-class\.
It allows virtually everything as valid rm\-object\.

This question causes me some headache\.

Thanks for opinions/answers
Bert

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## Post #2 by @thomas.beale

> Hi all,
>
> Please allow me a short question\.
>
> Is it allowed to define abstract types in archetypes,  I once saw an archetype which held an EVENT as attribute, so the constructor of the rm\-object which had to be validated against the archetype, could at runtime decide if he wanted to use a POINT\_EVENT or INTERVAL\_EVENT\.
> Is this allowed?

the runtime has to decide \(if not already decided by the archetypes or templates\) \- there is no choice\!

> Same can occur with data\_structures and data\_values\.
>
> Suppose \(theoretically\) an archetype which has LOCATABLE as definition\-class\.
> It allows virtually everything as valid rm\-object\.

it would but you can't state any interesting constraints with just LOCATABLE, so it is more likely to be something like EVENT\.

\- thomas

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## Post #3 by @system

Thanks, Thomas, for your confirmation, I was thinking this, but now I am sure\.

The question about Locatable was just to give an extreme example\.

regards
Bert

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**Canonical:** https://discourse.openehr.org/t/abstract-types-in-archetypes/15170
**Original content:** https://discourse.openehr.org/t/abstract-types-in-archetypes/15170