clojure.zip keywords

[Chas Emerick]

Having finally dug into clojure.zip and contrib's zip-filter, I
eventually needed a zipper? (or loc?) fn. Thinking I'd just check for
the existence of one of the keys in each loc's metadata, I noticed
that clojure.zip is using unusual keywords in that metadata, e.g.:

#^{:zip/branch? branch? :zip/children children :zip/make-node make-node}

I was fully expecting those keywords to be in the clojure.zip
namespace (e.g. ::branch? ::children? ::make-node); the way things are
now, they're in the zip namespace.

Is this correct/intentional? It feels like the code was written when
the reader had slightly different behaviour w.r.t. namespaced keywords.

- Chas