Pharo port

[Stuart Herring]

Hi all,

As I mentioned earlier, I've been working on a port to Pharo.
It's effectively a branch (not a fork), and can be found in the
MagmaPharo SqueakSource project.  The current version, which is based
on r42Gamma6 can be loaded via the MagmaPharo-42Gamma6-test3.mcm
Monicello Configuration Map.

It loads cleanly into Beta1 (10401) and 10413, and seems to work for
simple uses.  However, there's still some issues, and the tests do not
pass yet.

What I have had to change so far:

* Ma base additions:
  - Copied the extension methods from BlockContext to BlockClosure,
which has been previously discussed.
* Ma object serialization:
  - Removed the extension methods for classes no longer existent in
Pharo - meaning no more warnings when loading.
  - Created a new MaBlockClosureStorage class based on
MaBlockContextStorage, to handle the different internal representation
of a BlockClosure.  I'm not entirely sure of my handling of the
outerContext instVar though.
  - copied the extension methods from BlockContext, but modified them
to use MaBlockClosureStorage instead of MaBlockContextStorage, and to
call asBlockClosure not asBlockContext when materializing.
* Ma Armored Code
 - Replace the use of the missing ScreenController class with Display
 - Changes to the code to connect to localhost to support Pharo (
#connectTo:port: no longer accepts a ByteArray for the address - so
used SocketAddress loopback4 instead)
 * Ma object serialization tester:
 - removed the soundSamples method, due to the classes being tested no
longer existing.
 - Copied #maEquivalentForSerializationTest:... from BlockClosure to
BlockContext, modifying it to reflect the differences between the
classes.
* MagmaTester
 - replace usage of Utilities>>setAuthorInitials with Author>>initials
to prevent the tests being paused by deprecation warnings.  I'll have
to update it again now to use Author>>fullName Author>>initials was
also deprecated sometime after 10401.

As I said, the tests don't pass yet.
There's two immediate issues:
1. A Pharo bug - (issue 966) preventing MethodProperties from being
compared which causes the object serialization tests to fail.  I've
submitted a fix for that, which hopefully will make its way in.
2. Even with the MethodProperties fix, the sampleProcess serialization
tests fail.  This appears to be because a Process in Pharo has a
slightly different representation to one in Squeak - in Squeak, the
suspendedContext instVar is a BlockContext, in Pharo it's a
MethodContext.  After coming out of #maMaterializeFromGraph:, that
MethodContext in suspendedContext appears to be incomplete.  I haven't
been able to figure out why yet, probably because I haven't consumed
enough coffee to understand exactly what happens in the
serialization/materialization process.
In addition, some experimentation shows that some of the collection
tests may also fail, but I'll worry about that once the Process stuff
is dealt with.
Also, I don't think there's a version of NewCompiler that works with
Pharo yet, so there's no WriteBarrier support.

If anyone with a deeper understanding of either the serialization
process, or Processes, BlockClosures and MethodContexts wants to have
a look, please do!

The general idea of the MagmaPharo repository is that it should only
contain changes specifically required to make Magma work on Pharo,
general non pharo-specific changes should go to Chris and MagmaTester
as usual.
Whenever Chris publishes a new .mcm, I'll merge it into the MagmaPharo
repository, and then publish a new .mcm for Pharo, once I've verified
that all the tests still pass (assuming we've got to the point where
the tests do in fact pass).

Regards,
Stuart