Re: Proposal for a new mechanism for delayed stuff

[Karl Fogel <kfogel@red-bean.com>]

Lars Ingebrigtsen <larsi@gnus.org> writes:
>Gnus does a lot of stuff that it doesn't really know how long it'll take
>to do.  For instance, connecting to a mail server, and rendering
>complex HTML.
>
>If Gnus were to output "Connecting to foo", "sending retrieval
>commands", "waiting for foo to finish outputting" (which are usually
>done asynchronously, intermingled between many servers), Gnus would spew
>an inordinate number of messages.
>
>And sometimes the user should know what's taking so long, so that the
>user can decide what to do about it.
>
>So the ideal would be if we could say "display a message if things take
>too long".
>
>The idea I had yesterday was to make this totally general:
>
>(with-timeout-forms
>   (progn
>     (bla)
>     (bla))
>  (1.5 (message "This is sure taking a lot of time..."))
>  (10 (message "This is sure taking forever!")))
>
>A la condition-case and stuff, although here we have forms that are
>run if the main form takes too long.  So after 1.5 seconds we trigger
>the first, and after 10 we trigger the second.
>
>And perhaps it would also be possible to have a special thing in the
>timeout forms that would conclude the entire main form?  Like `return'
>or something.
>
>So it's like `with-timeout', only that it doesn't end executing the
>body.  And it would hopefully be possible to implement it such a way
>that a looping body form would also be "pre-emptible".  

I think that's a great generalization idea.  And `with-timeout' could
then be (re)implemented using `with-timeout-forms', presumably.