;;; Implementing environments as functions from names to values. 

(load "option.hfl")
(load "list-utils.hfl")

(def env-empty (fun (name) none)) 

(def (env-bind name val env) 
  (fun (n) 
    (if (sym= n name)
        val
        (env n))))

(def (env-bind-all names vals env)
  (foldr2 env-bind env names vals))

(def (env-lookup name env) (env name))