Specifying derivation rules

[dchristensen]

I've been trying to extend the SysML Requirement class, which has multiple derived properties that are defined in the stereotype itself. As part of the extension, I want to add more derived properties, but I haven't been able to figure out how the derivation rules for those properties are defined. The documentation for OCL (https://docs.nomagic.com/display/MD185/ ... t+Language) describes derivation rules, but does not explain how to define them. Is there a way to define the derivation rule in the stereotype itself and not in a customization?

I have attached an example project for the sake of illustration.

[dchristensen]

Oops. I forgot to upload the model I referenced in my last post. See attached.

[rjhudson@mitre.org]

This answer is most likely too late to be helpful for you, but I still wanted to answer for anybody else that may get stuck with this. The correct way to specify derived properties without using <<customization>> is to set the Default Value field to an opaque expression of type OCL2.0. Took me forever to find this, but it seems to work. Hope this helps.