From: Derek Peschel <dpeschel@...>
Date: 2001-10-22T16:53:27+09:00
Subject: [ruby-talk:22940] Most OO way to make a variation of the IO class?

Hi everybody,

Like other people on the list, I'm new to Ruby, and I'm quite pleased with
the "feel" of it.  I'm familiar with the concepts of OOP through Smalltalk
and C++, although I haven't actually written a lot of OO code.

I'm writing methods to translate between ASCII and FIO-DEC (a charcter set
used on the PDP-1, in the early 1960's).  Right now I'm worrying about the
algorithms, since FIO-DEC uses case-shifts like the 5-bit Murray code or
some of the modern Asian codes, but eventually I will want to use my methods
in a larger program.

And that leads up to my question.  I can imagine a "FIO-DEC IO" class that's
just like the ordinary IO except that it also translates.  Is there a simple
way to actually express that in Ruby?  Hopefully the new translation code
wouldn't have to worry about the implementation of the existing code; there
would be a small number of new methods to write; and only the class names
would have to be changed in the callers.

Unfortunately I suspect that the OO "is-a" relationship is too strict to be
relied on here.  It would be nice if I could change the putc and getc
methods and have puts and gets automatically change, or have I/O from/to
strings work as easily as I/O from/to files, but that doesn't mean it's
going to happen.

Thanks for any insight,

-- Derek