From: Tomtom <tomtom@herbesfolles.org>
To: guile-user@gnu.org
Subject: manipulating continuations
Date: Sat, 12 Feb 2011 09:35:06 +0100 [thread overview]
Message-ID: <4D56463A.6080508@herbesfolles.org> (raw)
Hello list
First of all, I'm new to scheme and guile - started using them a few
days ago for a project. So here we go: this is the bit of code that
causing me troubles:
(define (foo)
(call/cc
(lambda (return)
(display "first part")
(newline)
(call/cc
(lambda (cont)
(return cont)))
(display "second part")
(newline))))
Basically, I use call/cc to stop the procedure foo after printing "first
part" and return a continuation. Then, if I call this continuation it
prints "second part" and ends. To test this code, I did this:
guile> (define c (foo))
first part
guile> (c)
second part
yay, it works. But now, what if I want to run the continuation directly,
rather than storing it and calling it later ? This is what I get:
guile> ((foo))
first part
second part
Backtrace:
In current input:
15: 0* [#<unspecified>]
<unnamed port>:15:1: In expression ((foo)):
<unnamed port>:15:1: Wrong type to apply: #<unspecified>
ABORT: (misc-error)
There. I don't understand why I get this error message.
Cheers
Tom
next reply other threads:[~2011-02-12 8:35 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-12 8:35 Tomtom [this message]
-- strict thread matches above, loose matches on Subject: below --
2011-02-12 14:10 manipulating continuations Thomas Girod
2011-02-12 15:43 ` Andy Wingo
2011-02-12 16:40 ` Keith Wright
2011-02-12 17:16 ` Andy Wingo
2011-02-12 20:56 ` Thien-Thi Nguyen
2011-02-12 21:33 ` Andy Wingo
[not found] ` <1297887196-sup-8146@cresylol.hd.free.fr>
2011-02-17 11:08 ` Andy Wingo
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