[plt-scheme] unit-based servlet vs module-based servlet?

From: Jay McCarthy (jay.mccarthy at gmail.com)
Date: Wed Apr 11 22:21:48 EDT 2007

This is true. There are no differences in functionality, except the
API names/etc. I personally find the API of the module servlets
either. And I would be happy if no one used the units, so I could
delete the support. =)

Jay

On 4/11/07, Yin-So Chen <yinso.chen at gmail.com> wrote:
> I have written/test a couple of trivial module servlets and Robby you are
> correct - module servlets can be un/load without problems and the error
> doesn't seem to affect the servers.  So from what I can tell there are no
> discernible differences, perhaps until I run into very complex scenarios.
>
>
> Thanks!
> yinso
>
> On 4/11/07, Robby Findler <robby at cs.uchicago.edu> wrote:
> > On 4/11/07, Yin-So Chen <yinso.chen at gmail.com> wrote:
> > > Really?!  Not being familiar with the history of PLT scheme I have to
> say I
> > > am surprised by the answer - I would have thought module is an older
> > > concept.  Sounds like you are saying unit is slowly fading away?
> >
> > Oh, no! I wouldn't say that. It was just that, in the past, unit was
> > our top-level program structure, but we soon realized that units work
> > better as a general tool for constructing programs and we needed a
> > more first-order construct for just defining the top-level program
> > structure (in order to make compilation more tractable, etc).
> >
> > I'm using "we" in the loosest possible sense here. It was Scott Owens
> > and Matthew Flatt who really nailed down the difference and explained
> > it properly. Probably they can point you to some writings or say more
> > about it.
> >
> > > Can module based servlets be loaded/unloaded on demand like unit-based
> > > servlets?  And would badly written module servlet bring down the server?
> > > Unit servlets appear to handle the above fine, but if module servlet
> also
> > > works, then I am not sure if there are discernible differences (although
> > > there are still more unit-servlet examples in the doc).
> >
> > I think these questions are all answered the same way, regardless of
> > whether or not you use a module servlet or a unit servlet.
> >
> > I should probably defer to Jay, tho. There may be some issues I'm not
> > up to speed with in the web server.
> >
> > Robby
> >
> > > Thanks,
> > > yinso
> > >
> > >
> > > On 4/11/07, Robby Findler <robby at cs.uchicago.edu> wrote:
> > > > I suspect that most everyone wants to use module servlets these days,
> > > > not unit servlets. Once upon a time, we didn't have modules (and
> > > > servlets existed at that time), so we used units. Nowadays, modules
> > > > work much better with all of our other tools (like the compiler, for
> > > > example, but also the module browser and things like that), that you
> > > > really want your program to be in a module.
> > > >
> > > > That said, of course, if your program calls for the power of units,
> > > > use the units inside the module!
> > > >
> > > > Robby
> > > >
> > > > On 4/11/07, Yin-So Chen <yinso.chen at gmail.com> wrote:
> > > > > Hi all -
> > > > >
> > > > > yet another newbie question - what is the difference between
> unit-based
> > > > > servlet and module-based servlet and when to choose which?  Are the
> two
> > > > > comparable in terms of capabilities?  I look at the unit doc and
> notices
> > > > > that it is analogous to a pluggable component and hence appears to
> have
> > > more
> > > > > flexibility and power than module, so was wondering under what
> > > situations
> > > > > would a module servlet be preferrable over a unit servlet.
> > > > >
> > > > > Thanks,
> > > > > yinso
> > > > >
> > > > > --
> > > > > http://www.yinsochen.com
> > > > > ...continuous learning...
> > > > > _________________________________________________
> > > > >   For list-related administrative tasks:
> > > > >
> http://list.cs.brown.edu/mailman/listinfo/plt-scheme
> > > > >
> > > > >
> > > >
> > >
> > >
> > >
> > > --
> > >
> > > http://www.yinsochen.com
> > > ...continuous learning...
> >
>
>
>
> --
>
> http://www.yinsochen.com
> ...continuous learning...
> _________________________________________________
>   For list-related administrative tasks:
>   http://list.cs.brown.edu/mailman/listinfo/plt-scheme
>
>


-- 
Jay McCarthy <jay.mccarthy at gmail.com>
http://jay.teammccarthy.org


Posted on the users mailing list.