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<H1>[MUD-Dev] Re: DevMUD: Inheritable modules</H1>
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<LI><em>To</em>: <A HREF="mailto:mud-dev#kanga,nu">mud-dev#kanga,nu</A></LI>
<LI><em>Subject</em>: [MUD-Dev] Re: DevMUD: Inheritable modules</LI>
<LI><em>From</em>: Jon Leonard <<A HREF="mailto:jleonard#divcom,slimy.com">jleonard#divcom,slimy.com</A>></LI>
<LI><em>Date</em>: Fri, 30 Oct 1998 14:10:24 -0800</LI>
<LI><em>Cc</em>: Jon Leonard <<A HREF="mailto:jleonard#divcom,slimy.com">jleonard#divcom,slimy.com</A>></LI>
<LI><em>Reply-To</em>: <A HREF="mailto:mud-dev#kanga,nu">mud-dev#kanga,nu</A></LI>
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<PRE>
On Thu, Oct 29, 1998 at 09:00:20PM -0500, James Wilson wrote:
>
> On Thu, 29 Oct 1998, Jon Leonard wrote:
> >On Thu, Oct 29, 1998 at 06:53:29PM +0100, The Arrow wrote:
>
> >> It was something like this I thought of when I wrote the mail.
> >> The problem with interface inheritance, is how to export the interface.
> >> If the modules is written in C++ and we are using external inheritance
> >> (as described by Nicklas) the subclassing should be pretty simple. But how
> >> should the driver know what interface (and module) to use runtime?
> >
> >My current thoughts on this:
> >
> >I don't want to use C++, because it doesn't have the object model I want.
>
> can you elaborate?
More or less what I've said in other messages. You can't change the
implementation of a base class without (usually) forcing a recompile, you
can't query objects for what methods they support, you need to know object
interfaces at compile time. That sort of thing.
You can do these things in C++, but you wind up doing it in parallel with
the C++ module hierarchy. Why not do it in a language-portable way?
My thoughts on the matter would look something like:
struct func {
name *funcname, void *funcpointer, char *type_info;
};
Modules would export an array of these, more or less like this:
struct func interface[] = {
"get_message", get_message, "char*(char*,int,int,int)"
/* more like that */
NULL, NULL, NULL
};
Choose your type to name mangling to taste. There might be other elements of
struct func, like a documentation string, too.
> >An interface should have a name, and an array of function structures
> >like those exported by modules, except without the function pointers.
> >
> >We should have a source verifier that checks that the claimed interface
> >(name-mangled version of the function, or whatever) matches the prototype
> >of the function pointer.
> >
> >There should be a separate collection of defined interfaces, so a module
> >can just say "I implement interface X" (this can be verified, of course)
> >
> >This database of interfaces shouldn't be monolithic -- I don't want to have
> >to know about all interfaces that someone else might define.
> >
> >Explicit interfaces shouldn't be needed to make runnable MUDs, just
> >helpful in configuring them.
>
> did you see my proposal for how this could be done very easily in C++? the
> mapping is pretty straightforward.
The recent one with the modules full of declarations, not the earlier post
about using extern "C"? I've read all of the messages on MUD-Dev about
DevMUD (usually several times -- it's hard to remember everything reading it
only once.)
It looked plausible, but my primary point is that if we're going to invent
a different model to deal with dlopen sorts of issues, we should invent one
that works for C, C++, or nearly any other language. I prefer to write
modules in C, and if someone else writes in C++, we should interoperate.
Jon Leonard
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<li><strong><A NAME="00604" HREF="msg00604.html">[MUD-Dev] Re: DevMUD: Inheritable modules</A></strong>
<ul compact><li><em>From:</em> James Wilson <jwilson#rochester,rr.com></li></ul>
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<LI><STRONG><A NAME="00583" HREF="msg00583.html">[MUD-Dev] Re: DevMUD: Inheritable modules</A></STRONG>
<UL><LI><EM>From:</EM> Jon Leonard <jleonard#divcom,slimy.com></LI></UL></LI>
<LI><STRONG><A NAME="00584" HREF="msg00584.html">[MUD-Dev] Re: DevMUD: Inheritable modules</A></STRONG>
<UL><LI><EM>From:</EM> James Wilson <jwilson#rochester,rr.com></LI></UL></LI>
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<ul><li>Thread context:
<BLOCKQUOTE><UL>
<LI><STRONG>[MUD-Dev] Re: DevMUD: Inheritable modules</STRONG>, <EM>(continued)</EM>
<ul compact>
<LI><strong><A NAME="00573" HREF="msg00573.html">[MUD-Dev] Re: DevMUD: Inheritable modules</A></strong>,
Jon Leonard <a href="mailto:jleonard#divcom,slimy.com">jleonard#divcom,slimy.com</a>, Wed 28 Oct 1998, 23:46 GMT
<UL>
<LI><strong><A NAME="00579" HREF="msg00579.html">[MUD-Dev] Re: DevMUD: Inheritable modules</A></strong>,
The Arrow <a href="mailto:arrow#trelleborg,mail.telia.com">arrow#trelleborg,mail.telia.com</a>, Thu 29 Oct 1998, 17:56 GMT
<UL>
<LI><strong><A NAME="00583" HREF="msg00583.html">[MUD-Dev] Re: DevMUD: Inheritable modules</A></strong>,
Jon Leonard <a href="mailto:jleonard#divcom,slimy.com">jleonard#divcom,slimy.com</a>, Fri 30 Oct 1998, 00:48 GMT
<UL>
<LI><strong><A NAME="00584" HREF="msg00584.html">[MUD-Dev] Re: DevMUD: Inheritable modules</A></strong>,
James Wilson <a href="mailto:jwilson#rochester,rr.com">jwilson#rochester,rr.com</a>, Fri 30 Oct 1998, 02:14 GMT
<UL>
<LI><strong><A NAME="00602" HREF="msg00602.html">[MUD-Dev] Re: DevMUD: Inheritable modules</A></strong>,
Jon Leonard <a href="mailto:jleonard#divcom,slimy.com">jleonard#divcom,slimy.com</a>, Fri 30 Oct 1998, 22:18 GMT
<UL>
<LI><strong><A NAME="00604" HREF="msg00604.html">[MUD-Dev] Re: DevMUD: Inheritable modules</A></strong>,
James Wilson <a href="mailto:jwilson#rochester,rr.com">jwilson#rochester,rr.com</a>, Fri 30 Oct 1998, 23:58 GMT
<UL>
<LI><strong><A NAME="00682" HREF="msg00682.html">[MUD-Dev] Re: DevMUD: Inheritable modules</A></strong>,
Jo Dillon <a href="mailto:emily#thelonious,new.ox.ac.uk">emily#thelonious,new.ox.ac.uk</a>, Mon 02 Nov 1998, 10:17 GMT
<UL>
<LI><strong><A NAME="00696" HREF="msg00696.html">[MUD-Dev] Re: DevMUD: Inheritable modules</A></strong>,
James Wilson <a href="mailto:jwilson#rochester,rr.com">jwilson#rochester,rr.com</a>, Tue 03 Nov 1998, 03:18 GMT
</LI>
</UL>
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</LI>
<LI><strong><A NAME="00592" HREF="msg00592.html">[MUD-Dev] Re: DevMUD: Inheritable modules</A></strong>,
Niklas Elmqvist <a href="mailto:d97elm#dtek,chalmers.se">d97elm#dtek,chalmers.se</a>, Fri 30 Oct 1998, 13:15 GMT
</LI>
</UL>
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