Parsing Smalltalk with SmaCC
bergel at iam.unibe.ch
Fri Jun 29 13:28:42 UTC 2007
Thanks Ralph for this detailed explanation.
On 29 Jun 2007, at 13:42, Ralph Johnson wrote:
> SquekMap and Package Universe differ in at least two ways.
> The one that people notice immediately is that PU knows the
> prerequisites for a package. Thus, when you load a package in PU, you
> load all the packages that it depends on. This makes it much easier
> to use than SM. SM ought to be changed to do the same, and if it
> doesn't change then in my opinion it is likely to be abandoned.
> The second major difference is that there is one SqueakMap, and it
> tries to hold everything. There can be many databases for PU, on the
> other hand. One PU can include another. Each PU is supposed to have
> someone who oversees it and who makes sure that everything goes
> together. However, this last feature hasn't been used much. There
> was a PU for 3.9 and there is a different one for 3.10. But lots of
> different people stick stuff in the 3.10 "universe", and so it can
> take awhile before we discover that two packages don't work together.
> It is useful to have a complete list of packages. It would be a shame
> to abandon that feature of SM. Most of the time, however, I only want
> packages that are known to work with my current version.
> SM has some other features that PU doesn't, such as recording license
> info. PU can't uninstall a package, and I think SM allows this. It
> would be nice if PU added these features. But the strength of PU is
> that everything is supposed to work together, so PU is fundamentally
> at odds with the requirement to find every existing package.
> Edgar said that the 3.10 release team is going to drop SM. That is
> not entirely true. We have been moving packages out of the image, and
> PU makes that easier. When we move a package out of the image, we
> move it into PU. So, the plan is to move SM from the image to PU. It
> will still be available.
> The names of SM and PU seems wierd to me. Sicne SM tries to include
> everything, it should have been called "Squeak Universe". Since PU
> only contains packages that work toether, it shouldn't have been
> called "universe". Perhaps "galaxy", since there are many galaxies
> but only one universe.
Alexandre Bergel http://www.bergel.eu
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