Commit 330228d5 authored by Stefan Kangas's avatar Stefan Kangas

Provide default for describe-keymap prompt

* lisp/help-fns.el (describe-keymap): Provide a reasonable
default for prompt.  (Bug#30660)
(help-fns--most-relevant-active-keymap): New functions.

* test/lisp/help-fns-tests.el
(help-fns-test-find-keymap-name): New test.
parent 557b790e
......@@ -1562,17 +1562,55 @@ BUFFER should be a buffer or a buffer name."
(insert "\nThe parent category table is:")
(describe-vector table 'help-describe-category-set))))))
(defun help-fns-find-keymap-name (keymap)
"Find the name of the variable with value KEYMAP.
Return nil if KEYMAP is not a valid keymap, or if there is no
variable with value KEYMAP."
(when (keymapp keymap)
(let ((name (catch 'found-keymap
(mapatoms (lambda (symb)
(when (and (boundp symb)
(eq (symbol-value symb) keymap)
(not (eq symb 'keymap))
(throw 'found-keymap symb)))))
;; Follow aliasing.
(or (ignore-errors (indirect-variable name)) name))))
(defun help-fns--most-relevant-active-keymap ()
"Return the name of the most relevant active keymap.
The heuristic to determine which keymap is most likely to be
relevant to a user follows this order:
1. 'keymap' text property at point
2. 'local-map' text property at point
3. the `current-local-map'
This is used to set the default value for the interactive prompt
in `describe-keymap'. See also `Searching the Active Keymaps'."
(help-fns-find-keymap-name (or (get-char-property (point) 'keymap)
(if (get-text-property (point) 'local-map)
(get-char-property (point) 'local-map)
(defun describe-keymap (keymap)
"Describe key bindings in KEYMAP.
When called interactively, prompt for a variable that has a
keymap value."
(interactive (list
(intern (completing-read "Keymap: " obarray
(lambda (m)
(and (boundp m)
(keymapp (symbol-value m))))
t nil 'variable-name-history))))
(let* ((km (help-fns--most-relevant-active-keymap))
(val (completing-read
(format "Keymap (default %s): " km)
(lambda (m) (and (boundp m) (keymapp (symbol-value m))))
t nil 'keymap-name-history
(symbol-name km))))
(unless (equal val "")
(setq km (intern val)))
(unless (and km (keymapp (symbol-value km)))
(user-error "Not a keymap: %s" km))
(list km)))
(let (used-gentemp)
(unless (and (symbolp keymap)
(boundp keymap)
......@@ -125,6 +125,15 @@ Return first line of the output of (describe-function-1 FUNC)."
;;; Tests for describe-keymap
(ert-deftest help-fns-test-find-keymap-name ()
(should (equal (help-fns-find-keymap-name lisp-mode-map) 'lisp-mode-map))
;; Follow aliasing.
(defvaralias 'foo-test-map 'lisp-mode-map)
(should (equal (help-fns-find-keymap-name foo-test-map) 'lisp-mode-map)))
(makunbound 'foo-test-map)))
(ert-deftest help-fns-test-describe-keymap/symbol ()
(describe-keymap 'minibuffer-local-must-match-map)
(with-current-buffer "*Help*"
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