[DGD] preserving vars after lib recompile

[bart at wotf.org]

I use that as well, it works very well.

On Tue, 16 Sep 2008 12:11:39 -0700, Shentino wrote
> You can work around the "mutable libs" by simply creating an empty
> stub that does nothing but inherit the library.  The stub can be
> upgraded and cloned as needed, and the library would be freely
> destructable.
> 
> I think SkotOS does this.
> On Tue, Sep 16, 2008 at 11:49 AM,  <bart at wotf.org> wrote:
> > Assuming the following situation:
> >
> > library A compiled from /lib/a.c is only inherited, never used as an object in
> > its own right
> > object B compiled from /obj/b.c inherits /lib/a.c
> >
> > When you destruct A and then recompile B (without destructing it) no data in
> > variables will get lost regardless of if they are defined in /lib/a.c or
> > /obj/b.c, unless you happen to remove variables from the code (so they no
> > longer exist in the resulting object)
> >
> > The fact that you destruct A does not do anything to variables inherited from
> > it by B, those exist in the dataspace that belongs to B.
> >
> > If however A is also used as an object in its own right, any data in variables
> > for that object will get lost. This is one of the things that make attempts to
> > port more traditional libs to DGD and being able to take advantage of
> > persistence a lot more work then just porting to a slightly different LPC
dialect.
> >
> > At any rate, the old instance of A will continue existing until the last
> > program that inherits it is destructed or recompiled.
> >
> > When this happens a call to the driver object is made so it can do any
> > administration that might be needed.
> >
> > This may seem a bit strange since you destructed it, and indeed a
> > find_object() will not find it after the destruct. Internally, as a bit of
> > bytecode that is inherited by some objects it still exists however, as do any
> > variables it happens to define as part of the dataspaces of objects
inheriting it.
> >
> > Hope this helps :)
> >
> >
> > On Tue, 16 Sep 2008 09:30:32 -0700 (PDT), Noah Gibbs wrote
> >> This is a hard problem.  The Kernel lib solves it by not allowing
> >> data in libraries if I remember correctly.  You could also have
> >> upgrade scripts that saved off the data and reloaded it, but that
> >> will be ugly -- every object will have to maintain those scripts or
> >> upgrading will lose data...
> >>
> >> --- On Tue, 9/16/08, chris . <psych_mayo at hotmail.com> wrote:
> >>
> >> > From: chris . <psych_mayo at hotmail.com>
> >> > Subject: [DGD] preserving vars after lib recompile
> >> > To: dgd at dworkin.nl
> >> > Date: Tuesday, September 16, 2008, 8:17 AM
> >> > My understanding is that when i use an objectd to recompile
> >> > a lib, all the dependent files would be destructed and than
> >> > recompiled/recloned.  I want to preserve variables existing
> >> > in objects, whether or not they exist in that object or in a
> >> > lib the object inherits.
> >> > This issue has been discussed or worked on before i
> >> > presume, so i guess my first thought is to ask what other
> >> > people have done.
> >> > My ideas on the topic all involve writing an upgrade script
> >> > of some sort, for each object with variables to be saved.
> >> > Ive ruled out using save/restore.  I dont know of a way to
> >> > check what variables exist for a given object.
> >> > Thanks.
> >> > chris
> >> >
> >> >
> >> >
> >> >
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