Re: [9fans] dynamic module loading and versioning

["Bruce Ellis" <bruce.ellis@gmail.com>]

inferno is a bit more clever.  only the used functions from a load
of Sys are required.  everything is a module, tho many modules
are apps that can be run from whatever shell.  the code, if it be
jitted or not, is shared.  the module data is copied.  i like it.

strong type checking rules.

and it achieves the goal of making apps tiny.

brucee

On 4/19/06, Michael Baldwin <michael@cibernet.com> wrote:
> > the boundary is a bit blurred on inferno, because the explicitly
> > module loading there is most commonly used to load what on other
> > systems would be libraries.  but the result, at least as
> > implemented, has a very different feel from the shared library hell
> > on unix and windows.
>
> Aren't some of the same maintenance and versioning headaches
> associated with shared libraries still there with dynamic loading of
> modules?  In Inferno, occasionally the Sys module changes (just to
> pick a nasty one), and that can wreak similar havoc as incompatible
> shared libraries unless you have a flag day.  I've pondered playing
> with the PATH string in a module header to make this less burdensome,
> but I haven't seen anyone actually do it or even talk to the issue
> (OK, there aren't that (m)any users of Inferno to have people to ask,
> I know).
>
> It just seems that, if for some reason I go and change a function
> signature in the String module, say, isn't it a similar headache as
> shared libraries to keep all the programs that use the old and new
> module running and happy at the same time?  I know merely adding
> functions is still compatible, but sometimes incompatible changes
> must be made (int->big for file sizes and offsets comes to mind).
> And to keep old and new programs not just running but compiling is a
> bit of a bitch.  Has anyone thought about or addressed these issues
> in Inferno or another dynamic-loading system?  Any lessons that can
> be learned and brought back to the unwashed world of shared libraries?
>
>