Hurd OO (was Re: Unidentified subject!)

[Kalle Olavi Niemitalo <tosi@ees2.oulu.fi>]

Daniel Burrows <Daniel_Burrows@brown.edu> writes:

> What I saw was mostly interface-implementation
> stuff; for example, defining a filesystem interface and then having servers
> implement it by filling in the functions.  Is inheritence also supported, as
> in GTK+?

Some kind of inheritance is available via libdiskfs and such.
The libraries provide default definitions of functions, and the
program can override those if necessary; the linker sees two
functions with the same name and chooses the one in the program.
But this doesn't allow multiple implementations of an interface
within one program.

In message <m11w45E-000FONC@feynman.localnet> (1999-12-09,
Subject: Re: Perl support, concept proved), John Tobey suggested
putting an OO layer around libports.  That would make each port
an object with a virtual function for handling messages.  I don't
know if he implemented that.

Stacked translators naturally use delegation instead of
inheritance.