Don't use set union in appending nodes to Term?

Created by: dchandekstark

The use case is I want to append nodes to a term only if they are not isomorphic (RDF::Isomorphic) with an existing node. The << append method in Term uses set union on two Arrays, which relies on eql? and hash for comparison. It would be convenient if the method filtered out values using include?, which uses == for comparison, and so is more safely overridden in a Resource class (I think).

Another possibility I suppose is to fork how appending behaves based on whether the Resource class implements RDF::Isomorphic and/or an explicit option is given (isomorphic: true or something) in the property definition.

I am able to work around this (I would not call it a bug), but I'm asking the question to see what folks think.