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Re: [Scheme-reports] Bidirectional ports and port-open?

On Sun, Jul 1, 2012 at 1:19 PM, Marc Feeley <feeley@x> wrote:
> Formal Comment
> Submitter's name: Marc Feeley
> Submitter's email: feeley at iro.umontreal.ca
> Relevant draft: r7rs draft 6
> Type: defect
> Priority: major
> Relevant section of draft: 6.13.1. Ports
> Summary: Bidirectional ports and port-open?
> R7RS states that an implementation of Scheme may have bidirectional
> ports (because the input and output port types may not be disjoint).
> Bidirectional ports may be useful to represent operating devices such
> as serial ports, terminals, and network connections.  On some of these
> ports it is useful to close the input and output sides separately
> (for example closing the output side of a network connection on
> which a request was sent, while leaving the input side open to
> receive the response).
> For this reason, the procedure port-open? is not very informative for
> bidirectional ports.  It would be better to separate this into two
> procedures so that each direction can be tested independently:
>   (input-port-open? port)
>   (output-port-open? port)

Good point, formal comment ticket #439 created.


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