Re: E patches for review: ELoader

Here are some cleaned-up patches for adding ELoader. There are four in 
the series (on my "proposed" branch):

http://gitorious.org/~tal-itinnov/repo-roscidus/it-innovation/commits/proposed


They are:

"Added <elang:interp.ELoaderAuthor>"
http://gitorious.org/~tal-itinnov/repo-roscidus/it-innovation/commit/1c03d05489a596a474bd87d3ccdb6deee7819714

"Added seedVat/3 to give envExtras to the new vat"
http://gitorious.org/~tal-itinnov/repo-roscidus/it-innovation/commit/fcfa012324148163edc33f7a34a6de0f64d74d66

"When running (unconfined) code with rune, give it a <this> loader by
default"
http://gitorious.org/~tal-itinnov/repo-roscidus/it-innovation/commit/6e8e15eaf64d423d749bf66ce37533ec44e50854

"Set <this> loader when running updoc scripts"
http://gitorious.org/~tal-itinnov/repo-roscidus/it-innovation/commit/2f18c1519028a755f0fe6c1349ae914961ff2066


I agree with Kevin that a full module system needs more than this. In
particular, the ability to have public and private APIs for modules.
However, I think this would build on these patches rather than replace
them.

The code above never connects modules together itself; it just gives a
single <this> loader to .e and .updoc scripts. Programs wanting to use
multiple modules (e.g. my prototype) make a loader for each module and
connect them themselves. They can choose whether to give a module its
dependency's <this> loader directly, or some restricted facet of it.


Note: seedVat is still using the persistence sealer to transfer the
loader configuration between vats. This isn't a security issue because
seedVat already gives the caller <unsafe> in the new vat. I'm not sure
there's much advantage to using a different sealer; I think it would
just make it less likely that existing objects can be copied
successfully. It's up to the programmer not to copy an object that
shouldn't have two instances at once, just as they shouldn't revive two
vats from a single state file. I don't feel strongly about it either
way, though.



-- 
Dr Thomas Leonard
IT Innovation Centre
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