[eclipse-users] X = A or B

I have a constraint system with many constraints of the form:

X #= A1 or X #= A2 or ... or X #= An

On its own, this statement doesn't restrict the domain of X. Is there  
any we to re-express it so that the domain of X is maintained as the  
union of the domains of A1 ... An?

I don't suppose it would be too hard to program this directly (with a  
demon which is triggered by [A1,...An]->const) but if there's an  
existing solution I'd like to hear about it. Or if there is a  
compelling reason why maintaining this kind of relation is too  
expensive to be worthwhile.

Malcolm

--
       "An inconvenience is only an adventure wrongly considered;
        an adventure is an inconvenience rightly considered."
                 - G.K.Chesterton, On Running After Ones Hat