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Re: Positioning

This page is part of the web mail archives of SRFI 56 from before July 7th, 2015. The new archives for SRFI 56 contain all messages, not just those from before July 7th, 2015.

At Wed, 15 Sep 2004 10:00:15 +0200, Hans Oesterholt-Dijkema wrote:

Hi, and welcome to the discussion.

> Would it not be a good idea to add
>   file positioning primitives
> to an implementation for binary i/o.
> This would make 'record based' i/o possible, with
> seeks to records, etc; and it would be a logical
> next step, because binary i/o provides predefined
> sizes for 'variable types'.

It would indeed be a logical next step from a given view of ports,
however it's distinctly a _next_ step and I would rather a separate
SRFI deal with this, especially as it's already 1 day past the draft
period for SRFI-56.  I had considered this, and binary-typed ports,
and mmaped ports, and univorm vector block reads, but all of these
open a number of issues I'd rather not deal with.  Specifically with
positioning/seeking primitives, apart from interface (POSIX vs. other)
you have to deal with non-seekable ports, and are likely to get into
simultaneous input/output ports.  Scheme still has a long way to go on
its port API - for now it would be nice if, whatever those ports are,
we can read or write a single byte to them.