Expected behavior of Template AttributeDefinition with inconsistent sources

[Peter Schober]

* Takeshi NISHIMURA <takeshi at nii.ac.jp> [2019-07-18 17:59]:
> What is the expected behavior of Template AttributeDefinition with inconsistent sources?
> Undefined?

I don't know the answer to that but since you're scripting conditional
logic in Velocity here anyway you might as well add condionals for
that, too.
At which point the Velocity code will probably all but unreadable,
sadly, due to the (lack-of-)whitespace issue.

-peter