Call lisp function asynchronous

Call lisp function asynchronous

[Juraj Kubelka]

Hi!

Is it possible to call lisp function asynchronous?

I would like to use it with this intention: I have defined overlay on  
a region. And after few seconds I would like to delete this overlay.

          #'(lambda (overlay)
              (sleep-for 2)
              (delete-overlay overlay))

But I do not know how to call it without waiting for response  
(funcall delete-overlay overlay).
Can you help me?  Or is there better solution for it?

Thank you in advance.
Juraj

Re: Call lisp function asynchronous

[Katsumi Yamaoka]

>>>>> In <mailman.1698.1181180879.32220.help-gnu-emacs@gnu.org>
>>>>>	Juraj Kubelka wrote:

> Is it possible to call lisp function asynchronous?

It is possible but rather difficult to do it in earnest.  Good
examples are in emacs-w3m (http://emacs-w3m.namazu.org/).

> I would like to use it with this intention: I have defined overlay on
> a region. And after few seconds I would like to delete this overlay.

>          #'(lambda (overlay)
>              (sleep-for 2)
>              (delete-overlay overlay))

> But I do not know how to call it without waiting for response (funcall
> delete-overlay overlay).
> Can you help me?  Or is there better solution for it?

A timer seems to answer such a purpose.  For example:

#'(lambda (overlay)
    (run-at-time 2 nil #'delete-overlay overlay))

Re: Call lisp function asynchronous

[Juraj Kubelka]

On 7.6.2007, at 4:02, Katsumi Yamaoka wrote:

>>>>>> In <mailman.1698.1181180879.32220.help-gnu-emacs@gnu.org>
>>>>>> 	Juraj Kubelka wrote:
>
>> Is it possible to call lisp function asynchronous?
>
> It is possible but rather difficult to do it in earnest.  Good
> examples are in emacs-w3m (http://emacs-w3m.namazu.org/).
>
>> I would like to use it with this intention: I have defined overlay on
>> a region. And after few seconds I would like to delete this overlay.
>
>>          #'(lambda (overlay)
>>              (sleep-for 2)
>>              (delete-overlay overlay))
>
>> But I do not know how to call it without waiting for response  
>> (funcall
>> delete-overlay overlay).
>> Can you help me?  Or is there better solution for it?
>
> A timer seems to answer such a purpose.  For example:
>
> #'(lambda (overlay)
>     (run-at-time 2 nil #'delete-overlay overlay))

Yes, it is the solution.  Thank you a lot.
Juraj

Re: Call lisp function asynchronous

[Tim X]

Katsumi Yamaoka <yamaoka@jpl.org> writes:

>>>>>> In <mailman.1698.1181180879.32220.help-gnu-emacs@gnu.org>
>>>>>>	Juraj Kubelka wrote:
>
>> Is it possible to call lisp function asynchronous?
>
> It is possible but rather difficult to do it in earnest.  Good
> examples are in emacs-w3m (http://emacs-w3m.namazu.org/).
>

I believe you can only do asynchronous stuff with calls to external processes.
You cannot do it with other general functions. I think Emacs would need some
sort of thread support to do this. 


>> I would like to use it with this intention: I have defined overlay on
>> a region. And after few seconds I would like to delete this overlay.
>
>>          #'(lambda (overlay)
>>              (sleep-for 2)
>>              (delete-overlay overlay))
>
>> But I do not know how to call it without waiting for response (funcall
>> delete-overlay overlay).
>> Can you help me?  Or is there better solution for it?
>
> A timer seems to answer such a purpose.  For example:
>
> #'(lambda (overlay)
>     (run-at-time 2 nil #'delete-overlay overlay))

The timer will probably achieve what you want, but its not done asynchrously in
the true sense. If the operation associated with the timer is resource
intensive or long running, you are very likely to observe 'freezes'. 

Tim

-- 
tcross (at) rapttech dot com dot au

Re: Call lisp function asynchronous

[Barry Margolin]

In article <87myzbktwu.fsf@lion.rapttech.com.au>,
 Tim X <timx@nospam.dev.null> wrote:

> The timer will probably achieve what you want, but its not done asynchrously 
> in
> the true sense. If the operation associated with the timer is resource
> intensive or long running, you are very likely to observe 'freezes'. 

That's still truly asynchronous.  Asynchronous means that something 
happens automatically when some condition occurs, rather than being part 
of the sequential operation of the program.

Whether the main operation of the program continues in parallel is an 
orthogonal issue.

-- 
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
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