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; Improve documentation of :predicate in globalized minor modes

* doc/lispref/modes.texi (Defining Minor Modes):
* lisp/emacs-lisp/easy-mmode.el (define-globalized-minor-mode):
Improve documentation of the :predicate keyword in defining
globalized minor modes.
This commit is contained in:
Eli Zaretskii 2023-03-23 11:30:19 +02:00
parent 930b9fdd3a
commit bcd02cf512
2 changed files with 39 additions and 23 deletions

View file

@ -1775,6 +1775,8 @@ it's used to say which major modes this minor mode is useful in.
Any other keyword arguments are passed directly to the
@code{defcustom} generated for the variable @var{mode}.
@xref{Variable Definitions}, for the description of those keywords and
their values.
The command named @var{mode} first performs the standard actions such as
setting the variable named @var{mode} and then executes the @var{body}
@ -1860,9 +1862,10 @@ by visiting files, and buffers that use a major mode other than
Fundamental mode; but it does not detect the creation of a new buffer
in Fundamental mode.
This defines the customization option @var{global-mode} (@pxref{Customization}),
which can be toggled in the Customize interface to turn the minor mode on
and off. As with @code{define-minor-mode}, you should ensure that the
This macro defines the customization option @var{global-mode}
(@pxref{Customization}), which can be toggled via the Customize
interface to turn the minor mode on and off. As with
@code{define-minor-mode}, you should ensure that the
@code{define-globalized-minor-mode} form is evaluated each time Emacs
starts, for example by providing a @code{:require} keyword.
@ -1875,24 +1878,27 @@ Use @code{:variable @var{variable}} if that's not the case--some minor
modes use a different variable to store this state information.
Generally speaking, when you define a globalized minor mode, you should
also define a non-globalized version, so that people can use (or
disable) it in individual buffers. This also allows them to disable a
also define a non-globalized version, so that people could use it (or
disable it) in individual buffers. This also allows them to disable a
globally enabled minor mode in a specific major mode, by using that
mode's hook.
If given a @code{:predicate} keyword, a user option called the same as
the global mode variable, but with @code{-modes} instead of
@code{-mode} at the end will be created. The variable is used as a
predicate that specifies which major modes the minor mode should be
activated in. Valid values include @code{t} (use in all major modes,
@code{nil} (use in no major modes), or a list of mode names (or
@code{(not mode-name ...)}) elements (as well as @code{t} and
@code{nil}).
If the macro is given a @code{:predicate} keyword, it will create a
user option called the same as the global mode variable, but with
@code{-modes} instead of @code{-mode} at the end, i.e.@:
@code{@var{global-mode}s}. This variable will be used in a predicate
function that determines whether the minor mode should be activated in
a particular major mode. Valid values of @code{:predicate} include
@code{t} (use in all major modes), @code{nil} (don't use in any major
modes), or a list of mode names, optionally preceded with @code{not}
(as in @w{@code{(not @var{mode-name} @dots{})}}). These elements can
be mixed, as shown in the following examples.
@example
(c-mode (not mail-mode message-mode) text-mode)
@end example
@noindent
This means ``use in modes derived from @code{c-mode}, and not in
modes derived from @code{message-mode} or @code{mail-mode}, but do use
in modes derived from @code{text-mode}, and otherwise no other
@ -1902,13 +1908,15 @@ modes''.
((not c-mode) t)
@end example
This means ``don't use modes derived from @code{c-mode}, but use
@noindent
This means ``don't use in modes derived from @code{c-mode}, but do use
everywhere else''.
@example
(text-mode)
@end example
@noindent
This means ``use in modes derived from @code{text-mode}, but nowhere
else''. (There's an implicit @code{nil} element at the end.)
@end defmac

View file

@ -449,15 +449,23 @@ No problems result if this variable is not bound.
TURN-ON is a function that will be called with no args in every buffer
and that should try to turn MODE on if applicable for that buffer.
Each of KEY VALUE is a pair of CL-style keyword arguments. :predicate
specifies which major modes the globalized minor mode should be switched on
in. As the minor mode defined by this function is always global, any
:global keyword is ignored. Other keywords have the same meaning as in
`define-minor-mode', which see. In particular, :group specifies the custom
group. The most useful keywords are those that are passed on to the
`defcustom'. It normally makes no sense to pass the :lighter or :keymap
keywords to `define-globalized-minor-mode', since these are usually passed
to the buffer-local version of the minor mode.
Each of KEY VALUE is a pair of CL-style keyword arguments.
The :predicate argument specifies in which major modes should the
globalized minor mode be switched on. The value should be t (meaning
switch on the minor mode in all major modes), nil (meaning don't
switch on in any major mode), a list of modes (meaning switch on only
in those modes and their descendants), or a list (not MODES...),
meaning switch on in any major mode except MODES. The value can also
mix all of these forms, see the info node `Defining Minor Modes' for
details.
As the minor mode defined by this function is always global, any
:global keyword is ignored.
Other keywords have the same meaning as in `define-minor-mode',
which see. In particular, :group specifies the custom group.
The most useful keywords are those that are passed on to the `defcustom'.
It normally makes no sense to pass the :lighter or :keymap keywords
to `define-globalized-minor-mode', since these are usually passed to
the buffer-local version of the minor mode.
BODY contains code to execute each time the mode is enabled or disabled.
It is executed after toggling the mode, and before running