[rucksack-devel] Export

[Levente Mészáros]

> > running those lisp files will import the database into another
> > rucksack.
>
> Yes, I think that's possible.  I have the feeling that actually creating
> Lisp source files (that must be compiled/interpreted) is more complicated
> than necessary, but it's definitely possible.

I think it has many advantages over other proprietary formats (not
even talking about XML)
 - a lisper is already familiar with the syntax and semantics
 - the format is very concise
 - one can modify an exported database and use the full power of lisp
 - one doesn't need to write an interpreter/loader which imports that
data because it's already present in the vm

Of course there might be some disadvantages which I'm not aware of.

> > Storing the object -> identity during export
>
> Every persistent object already has a unique ID, so you could just use that
> during export.

Well you are right I could write that to the file.

> > and idenity -> object mapping during import
>
> The object table is basically an ID -> object mapping.  Maybe you could use
> that during import, I'm not sure.

This will not work. When the objects are recreated I cannot determine
the object id so I need a mapping from the one stored in the export
file to the one present in the rucksack where I am importing to.

> > Am I right that btrees are sufficient to make a map like a hashtable?
>
> Yes, in the sense that btrees provide a mapping.  No, in the sense that
> btrees do not have the typical hash table characteristics.

Could you be more specific on which characteristics do you think of?

Cheers,
levy

-- 
There's no perfectoin