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
