In article <[EMAIL PROTECTED]>, Scott David Daniels <[EMAIL PROTECTED]> wrote: > >An important help to some people's understanding of objects is >realizing how they are used. Sometimes an object is used to mediate >between the real world and a program. For example, you could design >an object which controlled a printer, and inserted line breaks a >page-ejects as needed. > >The "value" of the printer object is not safely replicable -- you >cannot copy the state of the printer object, attempt to print >something, and if there is a failure (like "out-of-ink") restore the >former state of the printer and try another method. The ink has run >out. Nothing in one exclusively in software can get you back to the >state where you had more ink. So for such things, the "state" of an >object is more than simply the rich detail of a data structure.
Yup. I sometimes say in such cases that the object is a proxy for some other object (sometimes real-world, sometimes not -- as in the case of a GUI object). -- Aahz ([EMAIL PROTECTED]) <*> http://www.pythoncraft.com/ "19. A language that doesn't affect the way you think about programming, is not worth knowing." --Alan Perlis -- http://mail.python.org/mailman/listinfo/python-list
