From: ··········@bbs.ee.ncu.edu.tw
Subject: What decides the destination of the stream ?
Date: 
Message-ID: <1131887300.675856.246290@o13g2000cwo.googlegroups.com>
The following codes are from "Successful Lisp" Charpter 23 .
I just can't understand what decides the destination of the stream in
the lambda function..
Any one can help me ?
Many Thanks!!

(define-condition high-disk-utilization ()
                    ((disk-name :initarg :disk-name :reader disk-name)
                     (current :initarg :current :reader
current-utilization)
                     (threshold :initarg :threshold :reader threshold))
    (:report (lambda (condition stream)
               (format stream "Disk ~A is ~D% full; threshold is ~D%."
                       (disk-name condition)
                       (current-utilization condition)
                       (threshold condition)))))
From: Rainer Joswig
Subject: Re: What decides the destination of the stream ?
Date: 
Message-ID: <joswig-4E9972.15431913112005@news-europe.giganews.com>
In article <························@o13g2000cwo.googlegroups.com>,
 ··········@bbs.ee.ncu.edu.tw wrote:

> The following codes are from "Successful Lisp" Charpter 23 .
> I just can't understand what decides the destination of the stream in
> the lambda function..
> Any one can help me ?
> Many Thanks!!
> 
> (define-condition high-disk-utilization ()
>                     ((disk-name :initarg :disk-name :reader disk-name)
>                      (current :initarg :current :reader
> current-utilization)
>                      (threshold :initarg :threshold :reader threshold))
>     (:report (lambda (condition stream)
>                (format stream "Disk ~A is ~D% full; threshold is ~D%."
>                        (disk-name condition)
>                        (current-utilization condition)
>                        (threshold condition)))))


CL-USER 1 > (define-condition high-disk-utilization ()
                    ((disk-name :initarg :disk-name :reader disk-name)
                     (current :initarg :current :reader
current-utilization)
                     (threshold :initarg :threshold :reader threshold))
    (:report (lambda (condition stream)
               (format stream "Disk ~A is ~D% full; threshold is ~D%."
                       (disk-name condition)
                       (current-utilization condition)
                       (threshold condition)))))
HIGH-DISK-UTILIZATION



The report function will be called by the Lisp system with the condition
and the stream.



CL-USER 3 > (error 'high-disk-utilization :disk-name "foo-disk" :current 0.9 :threshold 0.8)

Disk foo-disk is 0.9% full; threshold is 0.8%.
  1 (abort) Return to level 0.
  2 Return to top loop level 0.

Type :b for backtrace, :c <option number> to proceed,  or :? for other options

CL-USER 4 : 1 >
From: Pascal Bourguignon
Subject: Re: What decides the destination of the stream ?
Date: 
Message-ID: <87veywlhjo.fsf@thalassa.informatimago.com>
··········@bbs.ee.ncu.edu.tw writes:

> The following codes are from "Successful Lisp" Charpter 23 .
> I just can't understand what decides the destination of the stream in
> the lambda function..
> Any one can help me ?
> Many Thanks!!
>
> (define-condition high-disk-utilization ()
>                     ((disk-name :initarg :disk-name :reader disk-name)
>                      (current :initarg :current :reader
> current-utilization)
>                      (threshold :initarg :threshold :reader threshold))
>     (:report (lambda (condition stream)
>                (format stream "Disk ~A is ~D% full; threshold is ~D%."
>                        (disk-name condition)
>                        (current-utilization condition)
>                        (threshold condition)))))

It's an argument to the report function.  It's obviously the caller of
the function that decides which stream to pass.  Usually, the caller
of the report function of a condition is the error handler or the
debugger.  Usually, it will be *ERROR-OUTPUT*.

(handler-case
     (error 'HIGH-DISK-UTILIZATION :disk-name "A" :current 0.4 :threshold 0.35)
  (t (err) (with-output-to-string (*error-output*) 
              #+clisp(SYSTEM::REPORT-ERROR err))))

Note, it's the implementation specific function SYSTEM::REPORT-ERROR
which decides to write the error message to the *ERROR-OUTPUT* stream.


-- 
"You cannot really appreciate Dilbert unless you read it in the
original Klingon"
From: Timofei Shatrov
Subject: Re: What decides the destination of the stream ?
Date: 
Message-ID: <4377865e.30268475@news.readfreenews.net>
On 13 Nov 2005 05:08:20 -0800, ··········@bbs.ee.ncu.edu.tw tried to
confuse everyone with this message:

>The following codes are from "Successful Lisp" Charpter 23 .
>I just can't understand what decides the destination of the stream in
>the lambda function..
>Any one can help me ?
>Many Thanks!!

Lisp implementation. It outputs errors in a separate stream, but they
end up in REPL anyway. You can control it by binding *error-output* to
your own stream.

>
>(define-condition high-disk-utilization ()
>                    ((disk-name :initarg :disk-name :reader disk-name)
>                     (current :initarg :current :reader
>current-utilization)
>                     (threshold :initarg :threshold :reader threshold))
>    (:report (lambda (condition stream)
>               (format stream "Disk ~A is ~D% full; threshold is ~D%."
>                       (disk-name condition)
>                       (current-utilization condition)
>                       (threshold condition)))))
>

-- 
|a\o/r|,-------------.,---------- Timofei Shatrov aka Grue ------------.
| m"a ||FC AMKAR PERM|| mail: grue at mail.ru  http://grue3.tripod.com |
|  k  ||  PWNZ J00   || Kingdom of Loathing: Grue3 lvl 18 Seal Clubber |
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comp.lang.lisp / 2005 / nov