Meaning of Common Lisp Warning

Meaning of Common Lisp Warning

[Nordlöw]

What is the meaning of the compilation message
  Warning: cl package required at runtime

Should I never do
  (require 'cl)
in a package?

Is it because there is a todo to implement these algorithms as
builtins or what?

/Nordlöw

Re: Meaning of Common Lisp Warning

[Pascal J. Bourguignon]

Nordlöw <per.nordlow@gmail.com> writes:

> What is the meaning of the compilation message
>   Warning: cl package required at runtime
>
> Should I never do
>   (require 'cl)
> in a package?

This is not Common Lisp!

If you had written (require 'emacs-cl) it could have been Common Lisp,
(emacs-cl is a Common Lisp implementation written in emacs lisp).

But cl is an emacs "package" (nothing in common with Common Lisp
packages),  that provides a few Common Lisp like functions and macros.


> Is it because there is a todo to implement these algorithms as
> builtins or what?

No it is because the authors of emacs are stubborn.  They don't want
people to write emacs code with these common lisp like functions.

Just ignore this warning.

-- 
__Pascal Bourguignon__

Re: Meaning of Common Lisp Warning

[tomas]

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On Mon, Nov 30, 2009 at 12:49:35PM +0100, Pascal J. Bourguignon wrote:
> Nordlöw <per.nordlow@gmail.com> writes:

[...]

> No it is because the authors of emacs are stubborn.  They don't want
> people to write emacs code with these common lisp like functions.

To be fair, the whole truth is that there is a policy that core Emacs
packages don't depend on cl. So this warning might help to keep that
policy.

(On stubborness: many of us are stubborn. I am and I guess you are too.
It all depends on perspective. Sometimes stubborness is a Good Thing).

> Just ignore this warning.

Agreed: if you aren't aiming at developing a core Emacs package you can
safely ignore that.

Regards
- -- tomás
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Re: Meaning of Common Lisp Warning

[Lennart Borgman]

On Mon, Nov 30, 2009 at 3:17 PM,  <tomas@tuxteam.de> wrote:
> On Mon, Nov 30, 2009 at 12:49:35PM +0100, Pascal J. Bourguignon wrote:
>> Nordlöw <per.nordlow@gmail.com> writes:
>
>> No it is because the authors of emacs are stubborn.  They don't want
>> people to write emacs code with these common lisp like functions.


There has been subtle technical problems using the cl package because
of name clashes with Emacs functions/macros. I do not know if anyone
is sure they are resolved yet. (I have seen subtle problems.)


>> Just ignore this warning.
>
> Agreed: if you aren't aiming at developing a core Emacs package you can
> safely ignore that.


You can perhaps, but not people using your packages. Wouldn't it be
better to just follow the advice, use

   (eval-when-compile (require 'cl))

What is the problem with doing that?