diff options
Diffstat (limited to 'lisp/info-look.el')
| -rw-r--r-- | lisp/info-look.el | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/lisp/info-look.el b/lisp/info-look.el index f13900112fa..afe4301c659 100644 --- a/lisp/info-look.el +++ b/lisp/info-look.el @@ -306,6 +306,21 @@ If optional argument QUERY is non-nil, query for the help mode." (when (string-match (caar file-name-alist) file-name) (setq info-lookup-mode (cdar file-name-alist))) (setq file-name-alist (cdr file-name-alist))))) + + ;; If major-mode has no setups in info-lookup-alist, under any topic, then + ;; search up through derived-mode-parent to find a parent mode which does + ;; have some setups. This means that a `define-derived-mode' with no + ;; setups of its own will select its parent mode for lookups, if one of + ;; its parents has some setups. Good for example on `makefile-gmake-mode' + ;; and similar derivatives of `makefile-mode'. + ;; + (let ((mode major-mode)) ;; Look for `mode' with some setups. + (while (and mode (not info-lookup-mode)) + (dolist (topic-cell info-lookup-alist) ;; Usually only two topics here. + (if (info-lookup->mode-value (car topic-cell) mode) + (setq info-lookup-mode mode))) + (setq mode (get mode 'derived-mode-parent)))) + (or info-lookup-mode (setq info-lookup-mode major-mode))) (defun info-lookup-change-mode (topic) |