Self-interest September 2004

self-interest@lists.selflanguage.org

5 participants
5 discussions

Adding method slots dynamically
by oscar_lopez_p 16 Aug '05

16 Aug '05

Hello, How can I add dynamically a method slot to a self object? . I have: the method selector, the argument names and the body (source code) of a method, and I need (at runtime) to create a method from them and add it to an existing object. Thanks for the help, Oscar Lopez

3 3

Performance?
by Michael Latta 19 Oct '04

19 Oct '04

The Squeak list has postings for bytecodes/sec and sends/sec. Are similar figures avaialble for self? Is there a benchmark that can be run to get similar figures? I would be interested in knowing the relative performance of the two systems. Squeak seems to be running > 1000 cycles / bytecode. This seems quite high compared to the techniques used in the Self compiler, even with GC and compiler overhead. Michael

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About the situation of SELF
by Gustavo Quiroz 13 Sep '04

13 Sep '04

Hello. I have a very sìmple question: does anyone knows why SELF is no longer an official project at Sun Microsystems Laboratories? I can't seem to find the answer anywhere. Thank you very much. Gustavo Quiroz PUCP Lima - Peru

3 2

Re: prototype multiple dispatch creates uncollectable garbage?
by Brian T. Rice 03 Sep '04

03 Sep '04

James McCartney wrote: > This is a post I made on the self-list which I am reposting here with a > more attention getting subject line. > I am curious what the solution is, if there is one. I just joined the > list so perhaps this has been discussed. The archives don't appear to be > searchable. These last few days, I am really busy moving between apartments, and I had written a reply but lost it. For now, I will answer that yes this does seem to be a current problem, but, no, I can't figure out an actual realistic use-case for multi-methods applied at least partly to non-well-known (not reachable by name from the lobby) objects. We can handle method replacements, but disappearing roles are another issue. Note that re-loading code in principle should allow in-place library updating, not even having to swap objects, so there is a limit to the range of cases where it's needed. Probably the solution will have to involve a type of system-update notification system, kind of a feature which could be applied to have the effect of finalizers, as an example. Basically we'd need to trigger events when an object's map's roles are removed or otherwise invalidated. The problem is then that the system has to correctly identify which signature applies to the method. In general, method removal is tricky because there may be derived maps and so forth which also have the same signature. So there is a deficiency or gap in the things that the naive PMD configuration, but we're working on it. One factor that allows us not to address it is that our images can be built up rather easily, so we haven't been too concerned with removal yet. -Brian > On Aug 31, 2004, at 5:45 PM, Jecel Assumpcao Jr wrote: > >> Or even >> better, see the Prototype Multiple Dispatch in Slate: >> >> http://tunes.org/~eihrul/pmd.pdf >> http://tunes.org/~eihrul/talk.pdf >> >> and >> >> http://slate.tunes.org/ >> >> They currently use a very Self-like inheritance model, but plan to move >> in a different direction. > > One problem with the prototype multiple dispatch scheme, if I > understand it correctly, is that methods become uncollectable garbage > unless ALL of their specialized arguments are collectable. This is a > problem if you are multiple dispatching on arguments that live forever > like true, false and nil. Because roles are stored in each object that > participates in a method dispatch, once you define a method on an > object, that method lives as long as any of the argument objects lives. > This would make it tricky to create ephemeral objects with unique > behavior that use multiple dispatch. > > Hopefully one of the Slate folks can speak to this.. > ---end of original post--- > > for example see page 16 of talk.pdf. > The "encounter" methods cannot be garbage collected until both of their > referrers can be. In the case given it would not be a problem since > these are traits objects and presumably live for the life of the > program, but it would be a problem for a temporary object with unique > behavior.

2 2

Modifying Software
by Jack Waugh 03 Sep '04

03 Sep '04

I beg the group to forgive a question from someone with no experience with Self. My question concerns the effects of modifying a Self image while there are data in it. In Smalltalk, you can have a population of instances of some class in your image, and if you modify the class, the instances change their behavior accordingly. Self has no classes, and I suppose most programmnig modification is done by changing slots in the Lobby or by changing the objects (usually prototypes) to which those Lobby slots refer. So in Self, and in the actual practice of typical Self programmers, and with the support of typical Self programming environments, is there any way to modify software so that many existing objects change their behavior to reflect the modification?

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Self-interest September 2004