How to silence "Unknown slot" compiler warnings?

How to silence "Unknown slot" compiler warnings?

[Vitalie Spinu]

Hi,

I am getting loads of "Unknown slot" messages during compilation of my
package. Why are they happening and how can I silence them?

My use case is simple, define a class, create an object of that class and store
it in buffer local variable. Now, all instances of oref, oset and macros that
operate on those objects generate this warning.

Thanks,

  Vitalie


GNU Emacs 25.0.50.2 (x86_64-unknown-linux-gnu, GTK+ Version 3.16.7) of 2016-01-21

Re: How to silence "Unknown slot" compiler warnings?

[Stephen Leake]

Vitalie Spinu <spinuvit@gmail.com> writes:

> I am getting loads of "Unknown slot" messages during compilation of my
> package. Why are they happening and how can I silence them?

They happen because the byte compiler is pickier than you are about how
to spell the names of the slots.

> My use case is simple, define a class, create an object of that class and store
> it in buffer local variable. Now, all instances of oref, oset and macros that
> operate on those objects generate this warning.

Please post the code (or at least some of it), and the warnings.

-- 
-- Stephe

Re: How to silence "Unknown slot" compiler warnings?

[Vitalie Spinu]

>> On Mon, Feb 15 2016 15:13, Stephen Leake wrote:

> Please post the code (or at least some of it), and the warnings.

It's here:

 https://github.com/vspinu/polymode/blob/master/polymode-classes.el

I am always using :initarg with keywords because I want to emphasise slot names
in main code:

  (defclass pm-polymode (pm-root) 
  ((hostmode
    :initarg :hostmode


  Vitalie

Re: How to silence "Unknown slot" compiler warnings?

[Eric Abrahamsen]

Vitalie Spinu <spinuvit@gmail.com> writes:

>>> On Mon, Feb 15 2016 15:13, Stephen Leake wrote:
>
>> Please post the code (or at least some of it), and the warnings.
>
> It's here:
>
>  https://github.com/vspinu/polymode/blob/master/polymode-classes.el
>
> I am always using :initarg with keywords because I want to emphasise slot names
> in main code:
>
>   (defclass pm-polymode (pm-root) 
>   ((hostmode
>     :initarg :hostmode
>
>
>   Vitalie

You're using oref/oset with arguments as :tags, but the slot name should
just be a non-quoted, non-tag macro argument.

E

Re: How to silence "Unknown slot" compiler warnings?

[Eric Abrahamsen]

On 02/16/16 10:58 AM, Vitalie Spinu wrote:
>>> On Tue, Feb 16 2016 13:38, Eric Abrahamsen wrote:
>
>> You're using oref/oset with arguments as :tags, but the slot name should just
>> be a non-quoted, non-tag macro argument.
>
> What is this restriction for?
>
> That's the whole point of :initarg AFAIC. I need to use keywords to enhance
> readability of the code. There quite a few slots in my package and I want to
> distinguish then from local and global vars.

Initargs are still tags and only tags. But slot reference is only a
"naked" slot name (with oref/oset), or else a quoted symbol (with
eieio-{oref,oset}, or slot-value and set-slot-value). oref and oset are
just thin wrappers around the eieio-* versions.

I can't say why! I'm also a little uncomfortable about the "naked"
versions, and for the same reason -- my brain keeps seeing them as
variables.

> So I am afraid dropping keywords is not an option for me. Is there a way to
> selectively force shut compiler warnings in emacs?

That I couldn't tell you.

(Don't forget to follow-up to the list.)

Re: How to silence "Unknown slot" compiler warnings?

[Stephen Leake]

Eric Abrahamsen <eric@ericabrahamsen.net> writes:

> On 02/16/16 10:58 AM, Vitalie Spinu wrote:
>>>> On Tue, Feb 16 2016 13:38, Eric Abrahamsen wrote:
>>
>>> You're using oref/oset with arguments as :tags, but the slot name should just
>>> be a non-quoted, non-tag macro argument.
>>
>> What is this restriction for?
>>
>> That's the whole point of :initarg AFAIC. I need to use keywords to enhance
>> readability of the code. There quite a few slots in my package and I want to
>> distinguish then from local and global vars.
>
> Initargs are still tags and only tags. But slot reference is only a
> "naked" slot name (with oref/oset), or else a quoted symbol (with
> eieio-{oref,oset}, or slot-value and set-slot-value). oref and oset are
> just thin wrappers around the eieio-* versions.
>
> I can't say why! I'm also a little uncomfortable about the "naked"
> versions, and for the same reason -- my brain keeps seeing them as
> variables.

More importantly, it's a change from Emacs 24, that breaks a lot of
existing code.

Does this change make eieio consistent with some standard?

-- 
-- Stephe

Re: How to silence "Unknown slot" compiler warnings?

[Stefan Monnier]

> I am always using :initarg with keywords because I want to emphasise
> slot names in main code:

>   (defclass pm-polymode (pm-root) 
>   ((hostmode
>     :initarg :hostmode

:hostmode is not a slot name, it's an initarg name.  EIEIO is mostly an
implementation of CLOS, but for some reason it decided to allow you to
say (slot-value x :hostmode) instead of (slot-value x 'hostmode).

The two are equivalent, except that:
- (slot-value x :hostmode) is not accepted by CLOS.
- (slot-value x :hostmode) is slower.

> I can't say why! I'm also a little uncomfortable about the "naked"
> versions, and for the same reason -- my brain keeps seeing them as
> variables.

The "naked" version only shows up with (oref x hostmode) which is an
EIEIO-only macro which is equivalent to (slot-value x 'hostmode).
As you can see, the (slot-value x 'hostmode) version doesn't suffer from
this problem (and additionally it's part of CLOS), so I encourage you to
use that instead.
EIEIO can't take advantage of the compile-time-knowledge of `hostmode'
to speed up the slot access anyway, so you might as well use `slot-value'.

Both `oref' and `slot-value' are "namespace unclean" (they don't have
any kind of "package prefix"), but `oref' is a much more likely
candidate to obsolescence because `slot-value' at least has the argument
that it's a standard CLOS name.


        Stefan

Re: How to silence "Unknown slot" compiler warnings?

[Eric Abrahamsen]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

[...]

>> I can't say why! I'm also a little uncomfortable about the "naked"
>> versions, and for the same reason -- my brain keeps seeing them as
>> variables.
>
> The "naked" version only shows up with (oref x hostmode) which is an
> EIEIO-only macro which is equivalent to (slot-value x 'hostmode).
> As you can see, the (slot-value x 'hostmode) version doesn't suffer from
> this problem (and additionally it's part of CLOS), so I encourage you to
> use that instead.
> EIEIO can't take advantage of the compile-time-knowledge of `hostmode'
> to speed up the slot access anyway, so you might as well use `slot-value'.

Thanks! It's good to have a clear answer to that.