Path: utzoo!attcan!uunet!decwrl!ucbvax!bloom-beacon!ZURICH.AI.MIT.EDU!cph
From: cph@ZURICH.AI.MIT.EDU (Chris Hanson)
Newsgroups: comp.lang.scheme
Subject: with-input-from-file, with-output-to-file
Message-ID: <9008201754.AA12024@life.ai.mit.edu>
Date: 20 Aug 90 17:55:04 GMT
References: <1467@tub.UUCP>
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 52


   Date: 20 Aug 90 11:48:43 GMT
   From: Oliver Laumann <mcsun!unido!fauern!tub!net@uunet.uu.net>
   Organization: Technical University of Berlin, Germany
   Sender: scheme-request@mc.lcs.mit.edu

   I just noticed that the procedures with-input-from-file and with-output-
   to-file are in the draft R^3.99RS, but not in the P1178/D4 (the version
   from March 7, 1990).  Is this omission intended?  If so, why?

   Thanks,
   --
   Oliver Laumann     net@TUB.BITNET     net@tub.cs.tu-berlin.de     net@tub.UUCP


From "Differences between R4RS and Proposed IEEE standard", January
27, 1989:

    * The following procedures have an ill-defined semantics in the
    presence of the escape procedures produced by
    call-with-current-continuation.  In addition, we have two other
    mechanisms for opening files (open-{in,out}put-file,
    call-with-{in,out}put-file) rendering these unnecessary.

    A further complication is that these procedures bundle the action of
    opening a file with the (separate) action of binding the default
    (input or output) port.  In R4RS there is no orthogonal mechanism for
    binding the port; we propose such a mechanism (via
    with-input-from-port and with-output-to-port below) and suggest
    removing these "bundled" versions.  A reference implementation of
    these procedures is provided in an appendix.

	    with-input-from-file
	    with-output-to-file

From "IEEE/MSC/P1178 Working Group on Scheme: Unapproved Minutes of
Meeting", 3 February 1989:

    6.4  WITH-INPUT-FROM-FILE and WITH-OUTPUT-TO-FILE.

    The editors proposed replacing WITH-INPUT-FROM-FILE and
    WITH-OUTPUT-TO-FILE with WITH-INPUT-TO-PORT and WITH-OUTPUT-TO-PORT,
    respectively, since this made the dynamic binding of ports orthogonal
    to the opening of files.

    However, there was substantial concern that the semantics of any dynamic
    binding mechanism was ill-defined in the presence of escape
    procedures.

    Moved, seconded, and approved: delete WITH-INPUT-FROM-FILE and
    WITH-OUTPUT-TO-FILE, and do not add WITH-INPUT-FROM-PORT or
    WITH-OUTPUT-TO-PORT.