[syntax highlighting] functions highlighted as vars

[andreyorst]

I've disabled function highlighting, to bring color intensity a bit down by changing cider-font-lock-dynamically.
By default it is set to this:

'(macro core function var)

And I get the usual highlighting:

However if I remove core and function from this setting:

(setq cider-font-lock-dynamically '(macro var))

I get the following result after I load file:

Expected behavior

Steps to reproduce the problem

1. Download bug.zip, extract and run Emacs with provided minimal init.el:

$ unzip bug.zip
$ cd bug
$ emacs -q -l repro-init.el bug.clj

2. Jack in: Ctrl-cAlt-jy
3. Load bug.clj file with Ctrl-cCtrl-k

This results into the following highlighting:

Environment & Version information

CIDER version information

;; CIDER 1.0.0snapshot (package: 20201216.1330), nREPL 0.8.3
;; Clojure 1.10.1, Java 11.0.9.1

Emacs version

GNU Emacs 27.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.13) of 2020-12-23

Operating system

Fedora 33

[bbatsov]

So, to summarize you don't want the var highlighting, right?

Does this disappear if you do (setq cider-font-lock-dynamically '(macro))? I have a feeling the fact that pretty much everything is a var might be messing things up.

[andreyorst]

So, to summarize you don't want the var highlighting, right?

Umm, not quite. I do want dynamic vars to be highlighted, it is useful feature, I just don't want functions to be highlighted as vars. Removing var from cider-font-lock-dynamically surely removes highlighting, but that's not what I'm after.

I have a feeling the fact that pretty much everything is a var might be messing things up.

If CIDER can properly highlight functions, maybe this info can be used to unhighlight those? Or when highlighting a var check if it is a function var, if this even makes sense..

[bbatsov]

Yeah, my point was that probably the bug is related to the current definition of var. I don't remember this code well anymore, but I'll review it when I can. If you'd like to take a stab at this you can start here

cider/cider-mode.el

Line 751 in 4b6c0e9

(defun cider--compile-font-lock-keywords (symbols-plist core-plist)

[bbatsov]

In particular:

(cond ((and do-macro (nrepl-dict-get meta "macro"))
                              (push sym macros))
                             ((and do-function (or (nrepl-dict-get meta "fn")
                                                   (nrepl-dict-get meta "arglists")))
                              (push sym functions))
                             (do-var (push sym vars)))

I guess the bug is obvious here - if the function highlighting is not enabled everything becomes a var. Depending on your perspective this can be an issue or a feature. :-) I wonder why println didn't get the same treatment, though. Anyways, it seems that's going to be relatively simple to address.

[andreyorst]

wonder why println didn't get the same treatment, though

Perhaps because it is handled by core highligting separately. I've pushed a naive solution, hope this is enough