Add a mechanism for querying before executing a command

* doc/emacs/custom.texi (Disabling): Document it.
* doc/lispref/commands.texi (Disabling Commands): Document the
low-level stuff.

* lisp/simple.el (command-execute): Respect the `(query ...)'
value for `disabled'.
(command-execute--query): New function.
(command-query): New function.

1 files changed, 9 insertions, 0 deletions

diff --git a/doc/lispref/commands.texi b/doc/lispref/commands.texi
index 01aa1e1fa4b..a1628eabaa2 100644
--- a/doc/lispref/commands.texi
+++ b/doc/lispref/commands.texi
@@ -3945,6 +3945,15 @@ what happens when a disabled command is invoked interactively.
 Disabling a command has no effect on calling it as a function from Lisp
 programs.
 
+@findex command-query
+  The value of the @code{disabled} property can also be a list where
+the first element is the symbol @code{query}.  In that case, the user
+will be queried whether to execute the command.  The second element in
+the list should be @code{nil} or non-@code{nil} to say whether to use
+@code{y-or-n-p} or @code{yes-or-no-p}, respectively, and the third
+element is the question to use.  The @code{command-query} convenience
+function should be used to enable querying for a command.
+
 @deffn Command enable-command command
 Allow @var{command} (a symbol) to be executed without special
 confirmation from now on, and alter the user's init file (@pxref{Init