How to introduce new symbol bindings into a macro if necessary

template2.clj

; Introduce new variables with nested chunks of scope

(deftemplate my-template
  :aws-template-format-version "2010-09-09"
  :description "My description"
  (with-params [my-parameter {:type :string :description "My string parameter"}]
    (with-mappings [my-mapping
                    {:first-level-key-one {:second-level-key-one "Value"}
                     :first-level-key-two {:second-level-key-two "Another Value"}}]
      (with-conditions [my-condition (not my-parameter)
                        my-second-condition (= (-> my-mapping :first-level-key-one :second-level-key-one)
                                              my-parameter)]
        (resource my-instance aws.ec2/instance :image-id "ami-79fd7eee")
        {:my-first-output (:instance-type my-instance)
         :my-second-output my-parameter}))))

; Or just kind of introduce new bindings as they come up
(deftemplate my-template
  :aws-template-format-version "2010-09-09"
  :description "My description"
  :parameters [(param my-parameter
                 :type :string
                 :description "My string parameter")]
  :mappings [(mapping my-mapping
               :first-level-key-one
               {:second-level-key-one "Value"}
               :first-level-key-two
               {:second-level-key-two "Another Value"})]
  :conditions [(condition my-condition
                 (not my-parameter))
               (condition my-second-condition
                 (= (-> my-mapping :first-level-key-one :second-level-key-one)
                   my-parameter))]
  :resources [(resource my-instance
                aws.ec2/instance
                :image-id "ami-79fd7eee")]
  :outputs [(output my-first-output (:instance-type my-instance))
            (output my-second-output my-parameter)])