collecting properties from traversal?

[Per Bergman]

I have a tree, where each Vertex has a 'parent' edge. From a leaf I need to 
construct the path to the root, something like:

g.V("PUBLIC.Node:::13").repeat(out('parent')).until(out('parent').count().is(0)).path())
 

(or .tree())


What I need is to collect all properties from each Vertex in a list, while 
traversing.
Should I use a sack() or sideEffects(), or something else?


Thanks,
Per