macro.cljx

(ns strange.macros
 #+cljs  (:require-macros [cemerick.cljs.test :refer [is deftest]]
                   [strange.macros :refer [my-response edn]]))

;; I want an abstraction over a javascript library. These macros are simplified versions

#+clj
(defmacro my-response
  [x]
  (let [{:keys [status headers body]} x]
    `(+ ~status ~body)))
#+clj
(defmacro edn
  ;; ([body] `(edn 200 ~body))
  ([status body]
     {:status status
      :headers {"Content-Type" "application/edn"}
      :body `(pr-str ~body)}))

#+cljs
(deftest dummy-macro-tests
  ;; I use (+ [] {}) just to make sure the code is evaluated in javascript
  (is (= (my-response (edn [] {})) "[]{}")))
;; This is what I do with the real my-response
(comment
  ;;  inside a request handler
  (my-response response-object {:status 200 :headers {"Content-type" "..."} {:hello "world"}})
  (my-response response-object (edn {:hello "world"}))
)

Compiler yells this:

Caused by: java.lang.IllegalArgumentException: No value supplied for key: {}

this one works

#+clj
(defmacro parent
  "Given a map or a macro that expand to a map, do some calculation."
  [x]
  (let [{:keys [a b]} (macroexpand x)]
    `(+ ~a ~b)))

#+clj
(defmacro child
  "A macro that returns a map"
  [body]
  {:a [] :b `(pr-str ~(macroexpand body))})

#+cljs
(deftest dummy-macro-tests
  (is (= (parent {:a 2 :b 2}) 4))
  (is (= (parent (child {:hello "world"})) "[]{:hello \"world\"}"))
)

It turns out that cljsbuild auto sometimes compiles before cljx auto finishes which result the output javascript is a mix of old and new code. This macro itself is guiltless :)