Jank Support

[dannyfreeman]

We should consider having a way to support the Jank dialect of Clojure

Some interest is expressed here: jank-lang/jank#24

I would propose a new derivative mode, something like clojure-jank-ts-mode.

Jank supports some embedded code (c++). We could work to include a nested parser for this language. Good support for this may not land until Emacs 30. Currently nested parsers have a tendency to break out of their regions.

[sogaiu]

Wasn't sure which might be the relevant bits in Emacs, but came across this. Just leaving it here for future reference :)

Update: I guess that's the kind of thing you had in mind based on the code I see here -- (e.g. treesit-range-rules).

[bbatsov]

@rrudakov What are your thoughts on this? In general I'm not particularly interested in pursuing it, given that Jank is not very popular (yet), but if it's something easy, perhaps we can do it. I think here we need only syntax highlighting for C++ and nothing more.

[bbatsov]

Perhaps that's even more interesting for ClojureScript and its similar form js*:

(js* "10 + ~{}" 30)

[rrudakov]

In general I'm not particularly interested in pursuing it, given that Jank is not very popular (yet)

Basically I have the same thoughts.

It's indeed pretty easy, but I'm not a C++ expert. We would need to write a bunch of C++ queries and add appropriate faces. Perhaps we can look at c++-ts-mode as a reference.

[rrudakov]

Perhaps that's even more interesting for ClojureScript and its similar form js*:

(js* "10 + ~{}" 30)

This is interesting, I never used it myself. Where can I read more about this?

[bbatsov]

@rrudakov I think the API is the best resource https://cljs.github.io/api/cljs.core/#jsSTAR

[rrudakov]

@rrudakov I think the API is the best resource https://cljs.github.io/api/cljs.core/#jsSTAR

Not much here haha, I'll try to find some examples

[bbatsov]

This is what I got from ChatGPT:

[rrudakov]

OK, I tried it in REPL and it looks like it accepts an arbitrary JS code and executes it:

(js* "console.log('hello world')")

I wonder how widely it's used. I'm a bit hesitant to bring another parser and a bunch of queries unless it's highly desired. I'm ready to do that though :)

[rrudakov]

I've checked the new markdown-ts-mode in Emacs master and they use an interesting approach for code blocks. Basically they pull queries from corresponding major modes: https://cgit.git.savannah.gnu.org/cgit/emacs.git/tree/lisp/textmodes/markdown-ts-mode.el#n237. We can try something similar for Junk and JS I think.

[rrudakov]

With the following patch I was able to add JS syntax highlighting in js* forms:

diff --git i/clojure-ts-mode.el w/clojure-ts-mode.el
index c2dd69b..fe7e244 100644
--- i/clojure-ts-mode.el
+++ w/clojure-ts-mode.el
@@ -2511,6 +2511,37 @@ function can also be used to upgrade the grammars if they are outdated."
       (let ((treesit-language-source-alist clojure-ts-grammar-recipes))
         (treesit-install-language-grammar grammar)))))
 
+(defsubst clojure-ts--font-lock-setting-update-override (setting)
+  "Return enabled SETTING."
+  (let ((new-setting (copy-tree setting)))
+    (setf (nth 3 new-setting) t)
+    new-setting))
+
+(defun clojure-ts--harvest-treesit-configs (mode)
+  "Harvest tree-sitter configs from MODE.
+Return a plist with the following keys and value:
+
+    :font-lock (from `treesit-font-lock-settings')
+    :simple-indent (from `treesit-simple-indent-rules')"
+  (with-temp-buffer
+    (funcall mode)
+    (list :font-lock (seq-map #'clojure-ts--font-lock-setting-update-override
+                              treesit-font-lock-settings)
+          :simple-indent treesit-simple-indent-rules)))
+
+(defun clojure-ts--add-config-for-mode (mode)
+  "Add configurations for MODE to current buffer.
+
+Configuration includes font-lock and indent.  For font-lock rules, use
+the same features enabled in MODE."
+  (let ((configs (clojure-ts--harvest-treesit-configs mode)))
+    (setq treesit-font-lock-settings
+          (append treesit-font-lock-settings
+                  (plist-get configs :font-lock)))
+    (setq treesit-simple-indent-rules
+          (append treesit-simple-indent-rules
+                  (plist-get configs :simple-indent)))))
+
 (defun clojure-ts-mode-variables (&optional markdown-available regex-available)
   "Initialize buffer-local variables for `clojure-ts-mode'.
 
@@ -2618,7 +2649,18 @@ REGEX-AVAILABLE."
 (define-derived-mode clojure-ts-clojurescript-mode clojure-ts-mode "ClojureScript[TS]"
   "Major mode for editing ClojureScript code.
 
-\\{clojure-ts-clojurescript-mode-map}")
+\\{clojure-ts-clojurescript-mode-map}"
+  (when (treesit-ready-p 'javascript t)
+    (setq-local treesit-range-settings
+                (append treesit-range-settings
+                        (treesit-range-rules
+                         :embed 'javascript
+                         :host 'clojure
+                         :local t
+                         '(((list_lit (sym_lit) @_sym-name (str_lit (str_content) @capture))
+                            (:equal @_sym-name "js*"))))))
+    (clojure-ts--add-config-for-mode 'js-ts-mode)
+    (treesit-major-mode-setup)))
 
 ;;;###autoload
 (define-derived-mode clojure-ts-clojurec-mode clojure-ts-mode "ClojureC[TS]"

One problem is that if some JS node doesn't have a defined face (uses 'default' face) it's highlighted as Clojure string, which looks a bit awkward (the green color):

If I remove rule for Clojure strings, JS looks better, but normal strings are not highlighted:

I couldn't find a way to remove Clojure string highlighting only for js* forms. Will try to do some more experimenting.