Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!MCC.COM!maeda
From: maeda@MCC.COM (Christopher Maeda)
Newsgroups: comp.lang.scheme
Subject: Re : unwind-protect
Message-ID: <19881003111852.6.MAEDA@PELE.ACA.MCC.COM>
Date: 3 Oct 88 11:18:00 GMT
References: <16407@shemp.CS.UCLA.EDU>
Sender: daemon@bloom-beacon.MIT.EDU
Organization: The Internet
Lines: 26


    Date: 3 Oct 88 07:08:04 GMT
    From: pierce@locus.ucla.edu


    ** Subject: unwind-protect
    ** Message-ID: <10180@eddie.MIT.EDU>
    ** Date: 3 Oct 88 03:41:57 GMT
    ** Sender: uucp@eddie.MIT.EDU
    ** Reply-To: jbs@fenchurch.MIT.EDU (Jeff Siegal)
    ** Organization: MIT EE/CS Computer Facilities, Cambridge, MA
    ** Lines: 5
    ** 
    ** How can one do something like UNWIND-PROTECT in Scheme?  Is the
    ** concept completely ill-defined in the presence of first-class
    ** continuations, or is there an idiom which "sometimes works?"
    ** 
    ** Jeff Siegal

    Kent Dybvig's Chez Scheme has what seems to be a much more powerful construct
    called "dynamic-wind".  A brief sketch of its uses is given in Dybvig's
    "The Scheme Programming Language".

    -- Brad Pierce

Hmm.  How would unwind-protect be expressed with just call/cc?