Clojurescript macro and name mangling

Question

Context

I am using Clojurescript and I am trying to define a lot of functions at compile time to wrap a Javascript API. My code works fine with lower level of optimization of the compiler. Yes, when I use the :optimizations :advanced Clojurescript compiler flag, the compiler throws warning: Use of undeclared Var my.namespace/fname and my code does not work at runtime (some mangled symbol not found).

Here is a minimum example of the issue:

(defmacro create-a-function [l]
  `(defn ~l [o#] (inc o#)))

(create-a-function fname)

;; Below inside another function
(defn fname-clone [k]
  (fname k))

I decide a function called fname at compile-time using the macro create-a-function. When I try to call the function at runtime it fails.

What have I tried?

Lower optimization level: it works
Tested that the macro works fine at the repl
Using declare, like (declare fname), which gets rid of the warning at compile time but fails at runtime with the same error.

My question

How can I make this kind of code work with advanced level of optimization?

I am not able to reproduce your problem. I copy pasted your code and it works correctly here under advanced optimization. I assume you did put the macro in a separate clj or cljc file and import using require-macros? Also, what version of clojurescript are you running? I am on clojurescript 1.10.238 with shadow-cljs. I don't think shadow-cljs makes a difference here though.. — Hendrik Poernama

Michiel Borkent Michiel Borkent · Accepted Answer · 2018-06-02T11:56:16

I reproduced your code in this repo and it works.

Note that you have to put your macro in a .clj file.

When you want to use macros from a .cljc file in ClojureScript, use macrovich.

Clojurescript macro and name mangling

1 Answers