No comment syntax is defined #2903
Description
This issue reports a problem which was discussed in the clojurians forum.
I often get the following confusing message when debugging clojure macros in cider.
The basic problem is that when I'm debugging a clojure macro, the code within defmacro might very well throw an exception. Sometimes emacs ends up in a state where it is asking me for a comment character. I doubt this is information the user should be being asked.
To reproduce this, I've prepared a more-than-minimum working example.
You can download the repo,
git clone https://gitlab.lrde.epita.fr/jnewton/clojure-rte.git cd clojure-rte git checkout c2b73731462393540a254c7ed7f1b1cf01a72a1b You'll find a project.clj file in the top level directory.
Start up cider.
In the REPL paste the following but don't press ENTER>
(destructuring-case args [[] {}] (throw (IllegalArgumentException. "destructuring-fn, empty argument list not supported")) [[name & others] {name (not (or (satisfies symbol?) (= nil))) }] `(destructuring-fn nil ~@args) [[name] {}] (throw (IllegalArgumentException. "destructuring-fn, invalid function body or clauses clauses")) [[name lambda-list & others] {lambda-list (satisfies vector?)}] `(destructuring-fn-many ~@(if name (list name) nil) ;; either name or nothing (~lambda-list ~@others)) [[name & clauses] {clauses (and (satisfies list?) (not (= ())) (rte (:* (:cat (satisfies vector?) (:* :sigma)))))}] `(destructuring-fn-many ~@(if name (list name) nil) ;; either name or nothing ~@clauses) [[& others] {}] (throw (IllegalArgumentException. (cl-format false "destructuring-fn, invalid argument list: ~A" args))))With the cursor at the end of the expression, press C-c C-m, to open a new buffer cider-macroexpansion containing the following: (let [...] (rte-case ...))
(let [v15697 args] (rte-case v15697 (:cat) (let [[] v15697] (throw (IllegalArgumentException. "destructuring-fn, empty argument list not supported"))) (:cat (not (or (satisfies symbol?) (= nil))) (:* :sigma)) (let [[name & others] v15697] (seq (concat (list 'destructuring-fn) (list 'nil) args))) (:cat :sigma) (let [[name] v15697] (throw (IllegalArgumentException. "destructuring-fn, invalid function body or clauses clauses"))) (:cat :sigma (satisfies vector?) (:* :sigma)) (let [[name lambda-list & others] v15697] (seq (concat (list 'destructuring-fn-many) (if name (list name) nil) (list (seq (concat (list lambda-list) others)))))) (:cat :sigma (:* (and (satisfies list?) (not (= ())) (rte (:* (:cat (satisfies vector?) (:* :sigma))))))) (let [[name & clauses] v15697] (seq (concat (list 'destructuring-fn-many) (if name (list name) nil) clauses))) (:cat (:* :sigma)) (let [[& others] v15697] (throw (IllegalArgumentException. (cl-format false "destructuring-fn, invalid argument list: ~A" args)))) (:* :sigma) nil)) Navigate the cursor to the close paren of (rte-case ...), i.e. between the final and penultimate parens as shown here:
Now press m
You should now find yourself in the state where emacs is asking for a comment character
Environment & Version information
CIDER version information
;; CIDER 0.26.1 (Nesebar), nREPL 0.8.0 ;; Clojure 1.10.0, Java 11.0.7 Emacs version
Operating system
