[R6RS] [r6rs-discuss] port-position and set-port-position!

R. Kent Dybvig dyb at cs.indiana.edu
Sat Jun 30 14:33:25 EDT 2007

> I just noticed two oddities that were introduced
> in the 5.93 draft.  The first is that the
> description of port-position says it "returns an
> arbitrary value that is acceptable as input for
> set-port-position!".  This could be interpreted
> as requiring ports that support port-position to
> support set-port-position! also, which I hope is
> contrary to the editors' intent.

I've reworded to avoid this implication.

> The second is that the specification of
> open-string-input-port just says it is
> "implementation-dependent" whether the port
> supports port-position and set-port-position!,
> but the specifications of open-string-output-port
> and call-with-string-output-port say the port
> "should support the port-position and
> set-port-position! operations".  Why the
> asymmetry?

I've eliminated the asymmetry by changing the open-string-input-port
description to say "should support".  Change it the other way if you


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