(defmacro let-select
 "For each node or fragment, performs a subselect and bind it to a local, 
  then evaluates body.
  bindings is a vector of binding forms and selectors." 
 [nodes-or-fragments bindings & body]
  (let [node-or-fragment (gensym "node-or-fragment__")
        bindings 
          (map (fn [f x] (f x)) 
            (cycle [identity (fn [spec] `(select ~node-or-fragment ~spec))])
            bindings)] 
    `(map (fn [~node-or-fragment] 
            (let [~@bindings]
              ~@body)) ~nodes-or-fragments)))