Failure semantics are the obvious ones. At the very least you'll need some flavor of try { user.them.public_keys.primary.bundle } rescue {

Failure semantics are the obvious ones. At the very least you'll need some flavor of try { user.them.public_keys.primary.bundle } rescue { OhDamn } Less obvious is the potential for multiple targets. JWalk probably doesn't do this, but it could. For more ideas for how this could work take a look at http://research.microsoft.com/pubs/77415/theessenceofdataaccessincw(ecoop2005).pdf http://research.microsoft.com/pubs/77415/theessenceofdataacc...