This is also one of the things I suggested that'd be nice to have in the etcd API, along with an AST for boolean operations over guard expressions, more flexibl

This is also one of the things I suggested that'd be nice to have in the etcd API, along with an AST for boolean operations over guard expressions, more flexible comparators etc. You can emulate these with a sequence of independent transactions, but it'd be nice if the micro-transaction system were a tad more general.