*print-meta* in CIDER macroexpansions

[tsdh]

Although I have (set! *print-meta* true) at the REPL, when I do C-c RET on some macro form, the resulting *cider-macroexpansion*'s contents are not printed with their metadata.

This breaks debugging macroexpansion for me. I have macros that expand to code containing other macro calls, and I pass essential data from the outer macros to the inner macros using metadata. The expansion works correct in clojure, but I can't do it stepwise for debugging purposes in CIDER because the metadata isn't printed in the *cider-macroexpansion* buffer, and so expanding a macro in the expansion won't work.

Here is a minimal example that demonstrates the issue:

(in-ns 'user)

(defmacro defun-1 [name args & code]
  (when-not (:foo (meta name))
    (throw (RuntimeException. "No metadata")))
  `(defn ~name ~args ~@code))

(defmacro defun [name args & code]
  `(defun-1 ~(with-meta name {:foo true}) ~args ~@code))

(defun plus-1 [x]
  (inc x))

(plus-1 7)

Compiling the buffer prints 8, so the macroexpansion in Clojure works just fine. However, when you expand the (defun plus-1...) with CIDER, you cannot expand the resulting (defun-1 plus-1...) form anymore because the :foo metadata which defun attaches to the symbol plus-1 is gone (not printed).

So I'd be very happy with some customization option for enabling printing of metadata with CIDER macroexpansion. Alternatively, it could also just honor the *print-meta* value in the REPL.

[cichli]

Using the value set in the REPL definitely makes sense. For now, does using alter-var-root instead of set! work around the problem?

(alter-var-root #'*print-meta* (constantly true))

[tsdh]

No, sadly not.

[cichli]

Thanks for testing - I'll sort this out this evening.

[cichli]

@tsdh I've added the cider-macroexpansion-print-metadata option; setting that to true will cause the metadata to be printed. You might need a lein -U deps to grab the latest cider-nrepl if your lein has already checked today.

[tsdh]

@cichli Thanks, works perfectly!