ref: 3e51d386096b13c255d6aec4406f85548e9e7d63
parent: c70655587600ffeb4c5821e2008bd2b97bb7698a
author: Ori Bernstein <ori@eigenstate.org>
date: Fri Jan 31 10:56:23 EST 2014
Nomenclature change: cstr -> trait
We're calling these things traits now, although they really are
just constraints over types.