Hi.
Similar to Jakob, I have used traits in the past.
And I plan to use them again shortly.
In both cases, I have used them in conjunction with PetitParser for AST modelling - there are certain commonalities across the classes that don't necessarily conform to abstract/subclass hierarchies that have made them useful in the past (for my COBOL parser) and may also apply in the near future for my DB2 SQL parser. At least for the later, I'd prefer to implement what is needed in Traits instead of forcing the abstract superclass for the AST model.
And this time around I've been ruminating about adding the support needed to make this more useful for work as well. If there are other folks interested (sounds like Patrick and Jakob might be), then all the better.
cbc