New tree-sitter toggle scheme

This version: central variable, everything controlled by
treesit-settings.  Major mode sets up tree-sitter/non-tree-sitter
in a conditional branch, based on the setting.

* lisp/treesit.el (treesit-settings): New option.
(treesit-defun-type-regexp): Change docstring.
(treesit-mode-supported)
(treesit-required-languages)
(treesit--local-variable-backup): Remove variables.
(treesit--backup-local-variable)
(treesit-mode)
(global-treesit-mode--turn-on)
(global-treesit-mode): Remove functions.
(treesit--setting-for-mode): New function.
(treesit-ready-p): New argument MODE, changed REPORT to QUIET, and
LANGUAGEs to LANGUAGE (now it can be a single symbol or a list of
them).
(treesit-major-mode-setup): New function.  Mostly comes from
treesit-mode.

* test/src/treesit-tests.el (treesit-misc): New test.

* lisp/progmodes/python.el (python-mode): Move some setup code into
the conditional branch at the end.

* lisp/progmodes/js.el (js-json-mode)
(js-mode): Move some setup code into the conditional branch at the
end.

* lisp/progmodes/ts-mode.el: Move tree-sitter setup into the
conditional branch.

1 files changed, 21 insertions, 21 deletions

diff --git a/lisp/progmodes/python.el b/lisp/progmodes/python.el
index 4ac5f2e3b0a..2c0c35174c2 100644
--- a/lisp/progmodes/python.el
+++ b/lisp/progmodes/python.el
@@ -6391,15 +6391,6 @@ Add import for undefined name `%s' (empty to skip): "
 
   (setq-local forward-sexp-function python-forward-sexp-function)
 
-  (setq-local font-lock-defaults
-              `(,python-font-lock-keywords
-                nil nil nil nil
-                (font-lock-syntactic-face-function
-                 . python-font-lock-syntactic-face-function)))
-
-  (setq-local syntax-propertize-function
-              python-syntax-propertize-function)
-
   (setq-local indent-line-function #'python-indent-line-function)
   (setq-local indent-region-function #'python-indent-region)
   ;; Because indentation is not redundant, we cannot safely reindent code.
@@ -6424,14 +6415,9 @@ Add import for undefined name `%s' (empty to skip): "
   (add-hook 'post-self-insert-hook
             #'python-indent-post-self-insert-function 'append 'local)
 
-  (setq-local imenu-create-index-function
-              #'python-imenu-create-index)
-
   (setq-local add-log-current-defun-function
               #'python-info-current-defun)
 
-  (add-hook 'which-func-functions #'python-info-current-defun nil t)
-
   (setq-local skeleton-further-elements
               '((abbrev-mode nil)
                 (< '(backward-delete-char-untabify (min python-indent-offset
@@ -6479,13 +6465,27 @@ Add import for undefined name `%s' (empty to skip): "
 
   (add-hook 'flymake-diagnostic-functions #'python-flymake nil t)
 
-  (setq-local treesit-mode-supported t)
-  (setq-local treesit-required-languages '(python))
-  (setq-local treesit-font-lock-feature-list
-              '((basic) (moderate) (elaborate)))
-  (setq-local treesit-font-lock-settings python--treesit-settings)
-  (setq-local treesit-imenu-function
-              #'python-imenu-treesit-create-index))
+  (cond
+   ;; Tree-sitter.
+   ((treesit-ready-p 'python-mode 'python)
+    (setq-local treesit-font-lock-feature-list
+                '((basic) (moderate) (elaborate)))
+    (setq-local treesit-font-lock-settings python--treesit-settings)
+    (setq-local imenu-create-index-function
+                #'python-imenu-treesit-create-index)
+    (treesit-major-mode-setup))
+   ;; Elisp.
+   (t
+    (setq-local font-lock-defaults
+                `(,python-font-lock-keywords
+                  nil nil nil nil
+                  (font-lock-syntactic-face-function
+                   . python-font-lock-syntactic-face-function)))
+    (setq-local syntax-propertize-function
+                python-syntax-propertize-function)
+    (setq-local imenu-create-index-function
+                #'python-imenu-create-index)
+    (add-hook 'which-func-functions #'python-info-current-defun nil t))))
 
 ;;; Completion predicates for M-x
 ;; Commands that only make sense when editing Python code