bug#60407: [PATCH] Update go-ts-mode to use Imenu facility

[Eli Zaretskii]

> From: Evgeni Kolev <evgenysw@gmail.com>
> Date: Thu, 29 Dec 2022 18:05:49 +0200
> 
> This patch updates go-ts-mode to use Imenu facility added in
> https://git.savannah.gnu.org/cgit/emacs.git/commit/?h=emacs-29&id=b39dc7ab27a696a8607ab859aeff3c71509231f5
> 
> The Imenu items are extended to support "Method", in addition to
> "Function" and "Type".
> 
> The current Imenu approach uses "type_spec" to identify "Type" which
> acts as a catch-all for many Go constructs, for example struct and
> interface definitions. This catch-all approach is not optimal because
> structs and interfaces are put in the same "Type" bucket. In a
> follow-up patch I'll try to change the approach and have separate
> "Interface" and "Struct" types.
> 
> The patch is below.

Randy, Yuan, are you looking into this?

> commit 71ff7b21fe92167313bd1761b68b6e6fd879b09f
> Author: Evgeni Kolev <evgenysw@gmail.com>
> Date:   Thu Dec 29 17:49:40 2022 +0200
> 
>     Update go-ts-mode to use Imenu facility
> 
>     go-ts-mode is updated to use the Imenu facility added in commit
>     b39dc7ab27a696a8607ab859aeff3c71509231f5.
> 
>     The Imenu items are extended to support "Method", in addition to
>     "Function" and "Type".
> 
>     * lisp/progmodes/go-ts-mode.el (go-ts-mode--imenu-1) (go-ts-mode--imenu):
>     Remove functions.
>     (go-ts-mode--defun-name): New function.
> 
> diff --git a/lisp/progmodes/go-ts-mode.el b/lisp/progmodes/go-ts-mode.el
> index 124d9b044a2..c6c1c61d9f4 100644
> --- a/lisp/progmodes/go-ts-mode.el
> +++ b/lisp/progmodes/go-ts-mode.el
> @@ -173,44 +173,6 @@ go-ts-mode--font-lock-settings
>     '((ERROR) @font-lock-warning-face))
>    "Tree-sitter font-lock settings for `go-ts-mode'.")
> 
> -(defun go-ts-mode--imenu ()
> -  "Return Imenu alist for the current buffer."
> -  (let* ((node (treesit-buffer-root-node))
> -         (func-tree (treesit-induce-sparse-tree
> -                     node "function_declaration" nil 1000))
> -         (type-tree (treesit-induce-sparse-tree
> -                     node "type_spec" nil 1000))
> -         (func-index (go-ts-mode--imenu-1 func-tree))
> -         (type-index (go-ts-mode--imenu-1 type-tree)))
> -    (append
> -     (when func-index `(("Function" . ,func-index)))
> -     (when type-index `(("Type" . ,type-index))))))
> -
> -(defun go-ts-mode--imenu-1 (node)
> -  "Helper for `go-ts-mode--imenu'.
> -Find string representation for NODE and set marker, then recurse
> -the subtrees."
> -  (let* ((ts-node (car node))
> -         (children (cdr node))
> -         (subtrees (mapcan #'go-ts-mode--imenu-1
> -                           children))
> -         (name (when ts-node
> -                 (treesit-node-text
> -                  (pcase (treesit-node-type ts-node)
> -                    ("function_declaration"
> -                     (treesit-node-child-by-field-name ts-node "name"))
> -                    ("type_spec"
> -                     (treesit-node-child-by-field-name ts-node "name"))))))
> -         (marker (when ts-node
> -                   (set-marker (make-marker)
> -                               (treesit-node-start ts-node)))))
> -    (cond
> -     ((or (null ts-node) (null name)) subtrees)
> -     (subtrees
> -      `((,name ,(cons name marker) ,@subtrees)))
> -     (t
> -      `((,name . ,marker))))))
> -
>  ;;;###autoload
>  (add-to-list 'auto-mode-alist '("\\.go\\'" . go-ts-mode))
> 
> @@ -228,9 +190,18 @@ go-ts-mode
>      (setq-local comment-end "")
>      (setq-local comment-start-skip (rx "//" (* (syntax whitespace))))
> 
> +    ;; Navigation.
> +    (setq-local treesit-defun-type-regexp
> +                (regexp-opt '("method_declaration"
> +                              "function_declaration"
> +                              "type_spec")))
> +    (setq-local treesit-defun-name-function #'go-ts-mode--defun-name)
> +
>      ;; Imenu.
> -    (setq-local imenu-create-index-function #'go-ts-mode--imenu)
> -    (setq-local which-func-functions nil)
> +    (setq-local treesit-simple-imenu-settings
> +                `(("Function" "\\`function_declaration\\'" nil nil)
> +                  ("Type" "\\`type_spec\\'" nil nil)
> +                  ("Method" "\\`method_declaration\\'" nil nil)))
> 
>      ;; Indent.
>      (setq-local indent-tabs-mode t
> @@ -247,6 +218,18 @@ go-ts-mode
> 
>      (treesit-major-mode-setup)))
> 
> +(defun go-ts-mode--defun-name (node)
> +  "Return the defun name of NODE.
> +Return nil if there is no name or if NODE is not a defun node."
> +  (pcase (treesit-node-type node)
> +    ((or "function_declaration"
> +         "method_declaration"
> +         "type_spec")
> +     (treesit-node-text
> +      (treesit-node-child-by-field-name
> +       node "name")
> +      t))))
> +
>  ;; go.mod support.
> 
>  (defvar go-mod-ts-mode--syntax-table
> 
> 
> 
>