Templating of deftypes

1 desired deftype output.clj

(deftype MultiErrorReporter
  [reporters]
  ErrorReporter
  (constraint-error [_ state constraint]
    (into {} (for [[k ^ErrorReporter rep] reporters]
               [k (. rep (constraint-error state constraint))]))) 
  
  (extraneous-path-error [_ state extra-path]
    (into {} (for [[k ^ErrorReporter rep] reporters]
               [k (. rep (extraneous-path-error state extra-path))])))

  (missing-path-error [_ state missing-path]
    (into {} (for [[k ^ErrorReporter rep] reporters]
               [k (. rep (missing-path-error state missing-path))])))

  (predicate-fail-error [_ state val-at-path pred]
    (into {} (for [[k ^ErrorReporter rep] reporters]
               [k (. rep (predicate-fail-error state val-at-path pred))])))

  (instance-of-fail-error [_ state val-at-path expected-class]
    (into {} (for [[k ^ErrorReporter rep] reporters]
               [k (. rep (instance-of-fail-error state val-at-path expected-class))])))

  (pre-validation-transform-error [_ state val-at-path pre-validation-transform-fn]
    (into {} (for [[k ^ErrorReporter rep] reporters]
               [k (. rep (pre-validation-transform-error
                          state val-at-path pre-validation-transform-fn))]))))

2 approximate desired source.clj

(inject-forms
 (deftype MultiErrorReporter
     [reporters]
   ErrorReporter
   ^:splice methods)
 [methods `(do-template
            [method argvec] (method argvec
                                    (into {} (for [[k ^ErrorReporter rep] reporters]
                                               [k (. rep (name ~@argvec))]))) ;; yes, I'm aware ~@ doesn't work here -- it's to show my intent
            (constraint-error [_ state constraint])
            (extraneous-path-error [_ state extra-path])
            (missing-path-error [_ state missing-path])
            (predicate-fail-error [_ state val-at-path pred])
            (instance-of-fail-error [_ state val-at-path expected-class])
            (pre-validation-transform-error
             [_ state val-at-path pre-validation-transform-fn]))])