From 7dffe1868222f33c8845cac7b5e46836149c72f8 Mon Sep 17 00:00:00 2001 From: Noam Postavsky Date: Mon, 3 Oct 2016 18:49:56 -0400 Subject: [PATCH v1] Let describe-function work for lambda again Since commit "* lisp/help-fns.el (describe-function): More type checking[...]", `describe-function' throws a user-error when given a non-symbol. This prevents the [back] button in a *Help* buffer from working when the page it goes back to describes an anonymous function (e.g., the result of `describe-key' on a key which is bound to a lambda form). * lisp/help-fns.el (describe-function): Move the checks on FUNCTION being an fbound symbol into the `interactive' form. This allows non-interactive calls to pass an anonymous function (Bug #24221). Note that passing a non-bound symbol non-interactively will still trigger a `void-function' error from `describe-function-1'. --- lisp/help-fns.el | 33 +++++++++++++++++---------------- 1 file changed, 17 insertions(+), 16 deletions(-) diff --git a/lisp/help-fns.el b/lisp/help-fns.el index 26d8839..7dfa670 100644 --- a/lisp/help-fns.el +++ b/lisp/help-fns.el @@ -50,23 +50,24 @@ describe-function-orig-buffer ;;;###autoload (defun describe-function (function) - "Display the full documentation of FUNCTION (a symbol)." + "Display the full documentation of FUNCTION (a symbol). +When called from lisp, FUNCTION may also be a function object." (interactive - (let ((fn (function-called-at-point)) - (enable-recursive-minibuffers t) - val) - (setq val (completing-read (if fn - (format "Describe function (default %s): " fn) - "Describe function: ") - obarray 'fboundp t nil nil - (and fn (symbol-name fn)))) - (list (if (equal val "") - fn (intern val))))) - (or (and function (symbolp function)) - (user-error "You didn't specify a function symbol")) - (or (fboundp function) - (user-error "Symbol's function definition is void: %s" function)) - + (let* ((fn (function-called-at-point)) + (enable-recursive-minibuffers t) + (val (completing-read + (if fn + (format "Describe function (default %s): " fn) + "Describe function: ") + obarray 'fboundp t nil nil + (and fn (symbol-name fn))))) + (unless (equal val "") + (setq fn (intern val))) + (unless (and fn (symbolp fn)) + (user-error "You didn't specify a function symbol")) + (unless (fboundp fn) + (user-error "Symbol's function definition is void: %s" fn)) + (list fn))) ;; We save describe-function-orig-buffer on the help xref stack, so ;; it is restored by the back/forward buttons. 'help-buffer' ;; expects (current-buffer) to be a help buffer when processing -- 2.9.3