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Re: Last call

This page is part of the web mail archives of SRFI 106 from before July 7th, 2015. The new archives for SRFI 106 contain all messages, not just those from before July 7th, 2015.

On 06/30/2013 10:01 AM, Takashi Kato wrote:
On 30/06/2013 17:47, Per Bothner wrote:
For an input/output port there are two positions - because there are
actually two separate ports.
I disagree with this. It seems the point is mixed up with Java's problem
and how port should be. IMO input/output port doesn't have to (or even
must not) have two positions and it is one port.

No, the issue is not Java, but what a "port" conceptually is
(or should be): A "port" is a sequence of values, along with a current
position in that sequence.  An "input/output port" is not a sequence -
it is two sequences, along with two positions.

I.e. an input/output port is more naturally viewed as two distinct ports.
It is not in itself a port.  If you try to extend the concept of port to
include input/output ports then you no longer have a concept that has
that clean conceptual meaning.  Scheme should avoid such concepts.
	--Per Bothner
per@xxxxxxxxxxx   http://per.bothner.com/