Re: The equivalent of racket's break-thread in guile?

[Ludovic Courtès]

Xin Wang <address@hidden> skribis:

> 2013/5/31 Ludovic Courtès <address@hidden>
>
>> Xin Wang <address@hidden> skribis:
>>
>> > In Guile, the equivalent of kill-thread is cancel-thread, and is there
>> any
>> > equivalent of break-thread?
>> >
>> > [1] http://docs.racket-lang.org/reference/breakhandler.html
>>
>> If I understand correctly, “breaks” are similar to Guile’s “asyncs”
>> (info "(guile) Asyncs").
>>
>> However, I don’t understand what you’re trying to achieve.  Could you
>> give another example of the behavior you’re after?
>>
>>
> I was reading source code of Arc language[1], and wondering if it is
> possible to port it to Guile.
>
> It define a function to handle HTTP request in srv.arc(L48):
>
> (def handle-request-1 (s)
>   --- pruned ---
>             (with (th1 nil th2 nil)
>               (= th1 (thread
>                        (after (handle-request-thread i o ip)
>                               (close i o)
>                               (kill-thread th2))))
>               (= th2 (thread
>                        (sleep threadlife*)
>                        (unless (dead th1)
>                          (prn "srv thread took too long for " ip))
>                        (break-thread th1)
>                        (force-close i o))))))))
>
> It create two threads to handle a request, one do main stuff and anthor one
> wait to kill first one if it takes too much time.

Here ‘break-thread’ in the first thread appears to be equivalent to
Guile’s ‘cancel-thread’.

> Although I'm not quite sure, I think one reason to use 'kill-thread' and
> 'break-thread' differently is to make sure that exception handler function
> is fully executed. ('after' is implemented by  dynamic-wind).

Hmm, I guess I still don’t understand what ‘break-thread’ is supposed to do.

Ludo’.