doco with-input-from-file, with-output-to-file (was: documentation.scm close files)

[Kevin Ryde]

Marius Vollmer <address@hidden> writes:
>
> What about saying something about 'with-input-from', etc.

Speaking of these, I wonder if it could be a documented feature that
they use dynamic-wind to restore the current-input-port.  Currently
the docs follow the r5rs and don't say.

The behaviour in respect of the port itself would still be
unspecified, but getting current-input-port saved and restored nicely
seems a pretty sensible thing.  (Unless there's any prospect of an
r6rs going in a different direction. :-)