From: Jim Weirich <jweirich@...>
Date: 2002-02-28T10:17:58+09:00
Subject: Re: RCR 65: IO orthogonalization, improved reusability

>>>>> "Sean" == Sean O'Dell <sean@celsoft.com> writes:

    Sean> But where I/O is concerned, here's a base implementation
    Sean> that I use and have found very extensible to all sorts of
    Sean> streams.  Currently, I have stdio, file, sockets (plain and
    Sean> SSL), string and memory buffers using a system of class
    Sean> functionally identical to what I describe below:

[... Sean's example elided ...]

I think I'm looking for smaller, more cohesive abstractions, rather
than a single abstraction that handles reading, writing and random
seeking.

For example, an output stream would respond to puts, putc print,
printf, write and flush messages.  A simple implementation shell class
could be written in implement puts/putc/print/printf in terms of
write.  

I haven't given much thought to an input stream, but certainly it
should support read, readline, readlines, readchar, gets, getc, each,
each_line, etc, as well as eof/eof?.

A similar breakdown could be made for a random stream.

Then implementing an output stream could be as simple as implementing
write and mixing in OutputShell (or whatever) that implements all the
other methods in terms of write.  Or writing read and mixing in
InputShell to get an input stream.

I added an example of this to the http://www.rubygarden.org/ruby?IORCR
page on the RubyGarden wiki.

-- 
-- Jim Weirich     jweirich@one.net    http://w3.one.net/~jweirich
---------------------------------------------------------------------
"Beware of bugs in the above code; I have only proved it correct, 
not tried it." -- Donald Knuth (in a memo to Peter van Emde Boas)