contextual_eval.clj

(defn contextual-eval [ctx expr] ;; from Joy of clojure
  (eval 
    `(let ~(vec (mapcat #(list % `('~ctx '~%)) (keys ctx))) 
      ~expr)))


(defn contextual-eval  ;; alternative
  [ctx expr]
  (eval
   `(let ~(vec (apply concat ctx))
      ~expr)))