[self-interest] throwing light on The Effort on Self

Albertina Lourenci lourenci at lsi.usp.br
Mon Nov 22 11:37:59 UTC 1999

David Ungar wrote:

 In the  site  http://www.squeak.org/oopsla99_vmworkshop/    there is a
 nice paper from Mario, Ole and Dave  entitled Towards a universal
implementation substrate for object-oriented languages. It is put forward
clearly " even though the large number of Java systems currently in use
amply justifies the construction of a high-performance Java VM, Java
programmers today must make do with relatively underpowered virtual
machines. "
   They concluded " We have described implementations of Smalltalk and
Java which have respectable performance and yet were relatively easy to
construct in Self compared to traditional virtual machine implementations
in C and/ or C++. ....However, the connections between Java and Self are
much more tenuous, and yet the Java implementation was still easier to
build at least an order or magnitude compared to conventional approaches.
We encourage language designers and experimenters to use the Self
system in this way for their experiments."

Earlier in the paper they wrote "It would be interesting to broaden our
experience by implementing other object-oriented languages such
as Beta and Eiffel in this manner. This will undoubtedly expose further
deficiencies in the Self VM....Even so, we feel confident that many of the
constructs in other languages will map to Self ina clean and natural
way and that overall, implementing a language on top of the Self system
will be significantly easier than implementing it directly from scratch."

> >>  >
> >>  > > In my opinion, a minoritary language like Self should be developed
> >>  > > in a platform like Java VM. I am not a Java fan, but it provides a
> >>  virtual
> >>  > > machine in a variety of platforms, and also a "standard" graphical
> >>  > > environment. This would allow to get Self expansioned, I think.
> >>  > > Maybe, this is a bad idea because it would run too slowly, and
> >>  > > would become unusable (UI is now pretty slow, even in a UltraSparc).
> >>  >
> >>  > BTW, we once conducted a poll about what platform is the most
> >>  important
> >>  > to have Self running on. I can't recall the results right now, I
> >>  > think Windows and Linux have been rated most important, and Java
> >>  > was third place. (Please correct me if I'm wrong).
> >>

Obviously the reasoning above shows clearly the opposite direction. In a
workshop from ECOOP'97 in Finland about prototype-based languages
Luca Cardelli argued firmly about the superiority of the prototype based
languages and the difficulty of their taking off.  So I feel the hurdle
in persusading the computer scientists to direct their efforts towards this
goal. When I started implementing my Knowledge based systems
to design and plan sustainable cities in 1988, I did not make a compromise
with Pascal and C. I simply rejected them to discover that the object oriented
paradigm was created by Krysten Nygaard before the construction of the
first computer!!!!   I studied each object oriented language such as C++,
Eiffel, Sather, Beta and any interesting object oriented methodoloy and
also techniques from artificial intelligence such as Blackboard and multi
agents till I found Self.

So I think you should be courageous and choose the best, not to try to
limit the best to what is available or successful today.

And you should also remember that computer scientists do not have a
broader audience, because very few languages and methodologies do
mimic the sophisticated human cognitive processes. Until now I believe
Self is one of the best and yet a lot of must still be added to accompany
creative processes.

Best wishes


> >>  Has anyone suggested anything similar to the Slim Binaries used in
> >>  Oberon? These are, essentially, an intermediate parse tree, which can
> >>  be passed between platforms until actually used, at which point a code
> >>  generator builds the actual application in native code (much like the
> >>  JIT, but without the bytecode layer; it would cache this generated code
> >>  for future use). This has a number of advantages:
> >>
> >>  1) The parse tree is usually more compact than the bytecode equivalent.
> >>  2) It is language independent (sort of).
> >>  3) It allows greater optimization, as all of the high-level structure
> >>  is
> >>  accessible to the code generator.
> >>  4) All validation can be performed during the initial compilation,
> >>  making the Just-In-Time part faster.
> >>  5) It would still leave the possibility of a JVM implementation; in
> >>  fact, it would be considerably easier, as much of the work of compiling
> >>  is aleady done.
> >>  6) It would make rewriting the entire Self environment in Self a
> >>  practical option, provided there was an existing code generator on the
> >>  initial development platform.
> >>
> >>  OTOH, SB itself is not an 'open' technology, so we would probably have
> >>  to create our own equivalent (its copyrighted, but I don't think it is
> >>  patented, I'd have to check). Also, the claim that it is language
> >>  independent is rather questionable, at least in the existing system;
> >>  like the JVM, it is definitely targetted towards imperative/OO hybrid
> >>  languages, AFAICT.
> >>
> >>  Any comments?
> >
> >
> >
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> >
> >
> >
> >
> >
> >
> >
> >
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>      David Ungar
>      Sun Microsystems Laboratories
>      (650) 336-2618
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| Albertina Lourenci                                       |
| PhD  in Architecture and Urbanism                        |
| post-doctorate researcher                                |
| Laboratory of Integrated Systems University of Sao Paulo |
| Avenida Professor Luciano Gualberto, 158 Travessa 3      |
| CEP: 05508-900                                           |
| Sao Paulo Sao Paulo State Brazil                         |
| Voice: +55 011 818 5254                                  |
| Fax: +55 11 211 4574                                     |

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