Get rid of free variable warning from other packages?

Get rid of free variable warning from other packages?

[Steven Degutis]

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In my package, I setq some variables that are defined in other packages.
(Specifically, in ido-vertical-mode, I setq ido-decorations.) Is there a
way to disable the warning that says I'm setqing a free variable?

Or better yet, is there a better way to set a variable that belongs to
another package, only when my minor-mode is enabled, and have it reverted
back when my minor-mode is disabled?

-Steven

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Re: Get rid of free variable warning from other packages?

[Bob Proulx]

Steven Degutis wrote:
> ...  Is there a way to disable the warning that says I'm setqing a
> free variable?

Search for use of "eval-after-load" and you will find much discussion.

For example I routinely do things like this:

(eval-after-load 'text-mode
  (add-hook 'text-mode-hook
	    (lambda ()
	      (abbrev-mode 1)
	      (auto-fill-mode 1))))

I think you should be able to map that example into something useful
for your mode case.

> Or better yet, is there a better way to set a variable that belongs to
> another package, only when my minor-mode is enabled, and have it reverted
> back when my minor-mode is disabled?

Most configuration variables are already buffer local.

  http://emacswiki.org/emacs/BufferLocalVariable

  http://www.gnu.org/software/emacs/manual/html_node/elisp/Creating-Buffer_002dLocal.html

Bob

RE: Get rid of free variable warning from other packages?

[Drew Adams]

> In my package, I setq some variables that are defined in other
> packages. (Specifically, in ido-vertical-mode, I setq
> ido-decorations.) Is there a way to disable the warning that
> says I'm setqing a free variable?

(defvar ido-decorations)

IOW, a vacuous defvar: no value initialization.

> Or better yet, is there a better way to set a variable that
> belongs to another package, only when my minor-mode is
> enabled, and have it reverted back when my minor-mode is
> disabled?

A different topic (not "or better yet").

When your minor mode is turned on, save the current value of the other-package
variable in your own separate, internal variable.  When your mode is turned off,
restore the saved value.

This is not perfect, of course, since presumably other interactions while your
mode is active might change that package variable's value, so restoring (when
you exit your mode) the value it had when your mode was turned on might not be
the right thing to do.  It's a judgment call based on your particular context.

(OT - For key bindings, things are typically simpler: you can just define
bindings in your minor-mode map that shadow bindings in major modes (and in
other minor modes, if you can finagle things so yours come out on top).)

Re: Get rid of free variable warning from other packages?

[Steven Degutis]

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Thanks. That's actually what I currently do:
https://github.com/sdegutis/ido-vertical-mode.el/blob/master/ido-vertical-mode.el#L138-L165

The plugin in question: https://github.com/sdegutis/ido-vertical-mode.el

-Steven


On Tue, Apr 9, 2013 at 5:13 PM, Drew Adams <drew.adams@oracle.com> wrote:

> > In my package, I setq some variables that are defined in other
> > packages. (Specifically, in ido-vertical-mode, I setq
> > ido-decorations.) Is there a way to disable the warning that
> > says I'm setqing a free variable?
>
> (defvar ido-decorations)
>
> IOW, a vacuous defvar: no value initialization.
>
> > Or better yet, is there a better way to set a variable that
> > belongs to another package, only when my minor-mode is
> > enabled, and have it reverted back when my minor-mode is
> > disabled?
>
> A different topic (not "or better yet").
>
> When your minor mode is turned on, save the current value of the
> other-package
> variable in your own separate, internal variable.  When your mode is
> turned off,
> restore the saved value.
>
> This is not perfect, of course, since presumably other interactions while
> your
> mode is active might change that package variable's value, so restoring
> (when
> you exit your mode) the value it had when your mode was turned on might
> not be
> the right thing to do.  It's a judgment call based on your particular
> context.
>
> (OT - For key bindings, things are typically simpler: you can just define
> bindings in your minor-mode map that shadow bindings in major modes (and in
> other minor modes, if you can finagle things so yours come out on top).)
>
>

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Re: Get rid of free variable warning from other packages?

[Andreas Röhler]

Am 10.04.2013 00:13, schrieb Drew Adams:
[ ... ]
> (defvar ido-decorations)
>
> IOW, a vacuous defvar: no value initialization.
>


In Emacs Lisp, the symbol nil has two meanings. First, it means the empty list. Second, it means false and is the value returned when a true-or-false-test tests false.

http://www.gnu.org/software/emacs/emacs-lisp-intro/html_node/nil-explained.html

Or to say: nil means false, but false is more than nothing :)

Cheers,

Andreas

RE: Get rid of free variable warning from other packages?

[Drew Adams]

> > (defvar ido-decorations)
> > IOW, a vacuous defvar: no value initialization.
> 
> In Emacs Lisp, the symbol nil has two meanings. First, it 
> means the empty list. Second, it means false and is the value 
> returned when a true-or-false-test tests false.
>
http://www.gnu.org/software/emacs/emacs-lisp-intro/html_node/nil-explained.html
> Or to say: nil means false, but false is more than nothing :)

What's the relation to the text you quoted?

Re: Get rid of free variable warning from other packages?

[Kevin Rodgers]

On 4/9/13 1:30 PM, Steven Degutis wrote:
> In my package, I setq some variables that are defined in other packages.
> (Specifically, in ido-vertical-mode, I setq ido-decorations.) Is there a way to
> disable the warning that says I'm setqing a free variable?

(require 'foo) at the top level, where `foo' is the package that defines the
variables you want to set.

> Or better yet, is there a better way to set a variable that belongs to another
> package, only when my minor-mode is enabled, and have it reverted back when my
> minor-mode is disabled?

When the minor mode is enabled: (set (make-local-variable 'foo-bar) local-value)

When the minor mode is disabled: (setq foo-bar (default-value 'foo-bar))

-- 
Kevin Rodgers
Denver, Colorado, USA

Re: Get rid of free variable warning from other packages?

[Stefan Monnier]

> When the minor mode is disabled: (setq foo-bar (default-value 'foo-bar))

Did you mean (kill-local-variable 'foo-bar)?


        Stefan

Re: Get rid of free variable warning from other packages?

[Kevin Rodgers]

On 4/10/13 7:55 AM, Stefan Monnier wrote:
>> When the minor mode is disabled: (setq foo-bar (default-value 'foo-bar))
>
> Did you mean (kill-local-variable 'foo-bar)?

Still learning :-)

-- 
Kevin Rodgers
Denver, Colorado, USA