Self-interest February 2001

self-interest@lists.selflanguage.org

8 participants
9 discussions

Re: [self-interest] Digest Number 116
by Mario Wolczko 02 Mar '01

02 Mar '01

Stefan Matthias Aust writes: > Squeak notices if there's an error when it tries to display a morph. In > that case, a special flag is set so that this display method isn't called > again until somebody fixes the problem and manually resets that flag. A > flagged morph is displayed as a gray box with two crossing red lines. This is exactly what Self does (except for the gray box and red lines) - Randy and I put this code into 4.0, in '95 (before Squeak). See our CACM paper (vol 4, #4). When it was built, the UI was pretty robust -- we had numerous sessions with multiple users in the world at the same time, doing development. Randy and I demo'd this at ECOOP 95. If it's fragile now, it's because bitrot has set in somewhere, not because there is an inherent problem. Jecel writes: > For 32 bits, 2G is a positive number for C unsigned variables but a > negative number for signed ones. I took a quick look at space.c in the > VM sources but didn't get far enough to see if this could be your > problem. The VM has no idea how much real memory is installed. That certainly isn't the problem. Mario

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Self Style Question
by cramakrishnan＠acm.org 27 Feb '01

27 Feb '01

When creating a program in Self what's the convention for where to put your traits, globals, and oddballs? Do you put it with the system traits, globals, and oddballs or do you create your own namespace in your application for these things? - sekhar -- C. Ramakrishnan cramakrishnan(a)acm.org

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egroups has problems with thread structure ?
by Thilo Schwidurski 23 Feb '01

23 Feb '01

Hello, is there a way to post a reply *via email* *without* loosing the thread structure ? Did you make the same experience ? Anyway : I posted 954 as a reply to 946, 955 as a reply to 947 and 956 as a reply to 949. Regards, Thilo.

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information request
by Michael Lewis 13 Feb '01

13 Feb '01

Hi, Im interested in working/porting the self vm. Excuse my ignorance, but could someone please point me in the direction of the best starting place for documentation. N.B. Could someone please recommend a usefull text on this type of compiler technology - previous experiance has been producing relatively simple lexx/yacc procedural scripting languages. Rgds Michael Lewis -- lewis_michael(a)yahoo.com __________________________________________________ Do You Yahoo!? Get personalized email addresses from Yahoo! Mail - only $35 a year! http://personal.mail.yahoo.com/

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subjective programming
by Jecel Assumpcao Jr 05 Feb '01

05 Feb '01

I had been thinking about subjective programming lately, and happened to find an online version of the Us paper: A Simple and Unifying Approach to Subjective Objects (1996) Randall B. Smith, David Ungar http://citeseer.nj.nec.com/smith96simple.html Us is an extension of Self for subjective programming, and the only thing I had been able to find about it previously was this short position paper: The Subjective Prototype Randy Smith http://www-staff.mcs.uts.edu.au/~cotar/proto/randy.txt I first started considering objects with different viewpoints in terms of the user interface. On the previous version of this mailing list (in October 1990), I proposed that we could view objects through a set of "lenses". This Xerox project actually implemented this: http://www.parc.xerox.com/istl/projects/MagicLenses/ What an object looks like depends on what lens you view it through. Since another teacher at PUC-SP called my attention to the problem of "roles" in object oriented programming, I tried to include these features when I designed a Logo compatible, Self derived language in 1994. NeoLogo only allowed an object to extend one other object; a kind of "single inheritance". But this was very dynamic, so I came up with the idea of allowing multiple children to model the different roles for an object. There was a very complicated operation called AS. So the expression X AS Y would: - return Y if Y was a child of X - return Y if X was a child of Y (true! this rule was to allow AS to work as a kind of resend) - return Z if Z was a clone of Y and Y was a child of X - return Z if Z was a clone of Y, W was a clone of X and Z was a child of W - signal an error, otherwise There was also an ASNEW that was just like this, but instead of returning an error in the last case it created a new clone of Y that would satisfy one of the previous two rules. This seemed to solve the magic lenses and roles problems, so I was surprised at Ecoop95 by a paper claiming that delegation (what I was using could be considered that) wasn't the right tool for this job: Sharing Properties in a Uniform Object Space Heiko Kießling and Uwe Krüger http://link.springer.de/link/service/series/0558/bibs/0952/09520424.htm Their system seems similar to the Beta language in many ways, but they allow a single object to have several views. An advantage over my idea was that objects didn't change identity when you changed views. The Us language has this advantage as well. And the view is defined as a part of the sending context which is by default inherited by the receiving context. This means that many objects change when you change views (AS in NeoLogo encoded the view in the object identity and so only the receiver was affected - all other objects looked the same as before. NeoLogo also had the nasty "rubber band" semantics described in the Us paper). While the paper introduces a new syntax for changing views, we could use the existing Self parser and bytecodes by doing something like [ some expressions ] >< newView The examples of how it could replace meta-objects for reflection and how they could be used for versions and multi-user objects were particularly interesting for me. With some additional semantics (if you could have copy-on-write views) you could even use them for transactions: if you throw away a transactionLayer and let the garbage collection have it, it is an abort; but if you explicitly merge it with another view then that is a commit. Of course, multiple graphical views are interesting too and the reason I was thinking about all this. I wanted to do a graphical version of my CMOS simulator but needed a schematic view, a layout view, a component view, a simulated schematics view, a simulated layout view and so on. My design was to create a copyAs: method which would copy "split objects" as indicated by view objects (special dictionaries). I have no idea of how to implement this efficiently, but was wondering if the people in this list (specially Randy and Dave) think it is a worthwhile idea. -- Jecel

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SELF for VisualWorks 5i
by Stefan Matthias Aust 03 Feb '01

03 Feb '01

Hi! I spend a few more hours on Gordon's SELF for Smalltalk code (http://groups.yahoo.com/group/self-interest/message/973) and finally reach a state were it was able to completely read in the "core/init.self" file. This doesn't really mean you can already use it, but now there's a much better chance that the parser and interpreter work correctly and it shouldn't be that difficult to start trying to read in the other bootstrap files from the original SELF distribution. Just add three dozens more primitives... :-) If you're interested, you can get the source from my webpage at www.3plus4.de/self/. You need a VisualWorks 5i Smalltalk to load the code. The page contains instructions how to get a free non-commercial version. bye -- Stefan Matthias Aust \\ Truth Until Paradox

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Looking for myself source
by sma＠3plus4.de 03 Feb '01

03 Feb '01

Hi! It's awkward to ask, but I wonder whether somebody here downloaded the "myself for Smalltalk" code I published two years ago and would now send it to me again. I can't find that version anymore on my disks :-( You'd do me a great favor. bye -- Stefan Matthias Aust \\ Truth Until Paradox!

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UNSUBSCRIBE
by Gordon F. Cichon 03 Feb '01

03 Feb '01

UNSUBSCRIBE

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First
by Stefan Matthias Aust 02 Feb '01

02 Feb '01

Hi! Yesterday, I played two hours at my company with a real Self system (version 4.1.2). Only my colleague was more excited than I was, even if he didn't know anything about Self and was just playing around with the UI, recoloring and resizing windows and watching me searching the system to find out how to make cursor keys workable. It was fun even if it's a five years old system. Although I've a few questions and comments. In random order... The first time, the system crashed was when it said it couldn't allocate more than 130 MB of memory. I don't know why it wanted that much memory and frankly, I don't care. However, my system has 2048 MB of memory, so my question is, why couldn't it allocate more memory. The second time, the system crashed was when I assigned a number to a label morph (probably instead of a string). I agree with my colleague, the UI seems to quite fragile. Self tried to open a new world but still, it flooded my with debuggers. I like the way Squeak deals with display errors much better. Opening a morph factory freezes the whole system for 5-20 seconds. I think, this is unacceptable for a multi user system. I've run Self on a 2 x 440MHz SPARC system. It could be the multi user display or simply the age of the system, but compared to VisualWorks on the same system, Self feels slow on the UI. It seems that the Smalltalk emulator is missing in the current distribution. The web browser throws an exception because a paint mgr doesn't understand some messages. It seems, there're some 24 bit-depth bugs. From time to time, I got strange errors like 4673826438 doesn't understand asVMByteVector (so some similar message, I don't exactly remember), perhaps because some missing 24 bit-depth support? When using the multi user mode, shouldn't every user have his own radarView morph which is inaccessable for every other user? Now, by navigating away, I was able to leave my colleague alone on the start screen which no chance to follow me. We then duplicated a viewer but now two or more viewers always cluttered the screen. The system wasn't able to get our names. Both mouse pointer were called "Andre" which is the forename of first employee in the passwd file but neither my nor my colleagues name. I love the core sampler! (This had to be said ;-) When changing methods, that's the best way to collect changes to post or publish them? There's changed modules morph, but it seems that it can only write complete modules. It also crashes if the directories it assumes don't exist. Is it correct that there's no change set concept as in Smalltalk? It seems the Self image contains all source code. Why? Wouldn't it be better to have a system similar to Smalltalk where source code and changes are stored in external files and the image would contain only pointers to that files? I really missed Squeak "revert" and "versions" menu commands. They're easy to implement once you've the concept of a changes file. When I was playing with the system trying to colorize a propertiesSheet morph, I managed to color it red but then lost track what I'd changed and couldn't find the place again. Is there a way to list and browse changed methods - and as multiple people can change methods, sorted by user? What's the best way to change the value of an assignable slot (the one marked with ":"). I tried to open some kind of inplace editor but that seems to work only for the slot name, not the slot value. So I always had to open a shell for that object and evaluate things like "width: 2". At least for simple literals, it would be nice if you could directly enter the new value. Does the text editor require a non-proportial font? Or is any font possible? How can I change that? What's about the font size? Is there a way to automatically update object outiners? When I change values, it seems that the new values are shown after a short time but I don't know whether this is a feature or simply happened by accident because the morph was redisplayed. A manual update option would be nice. It also would be nice if all "tools" would behave and look the same. I dislike the fact that most tools don't have a close button. Interestingly, in the barebone image, the debugger has one while in the demo image, it has an "abort" push button. But overall, Self is really cool. How I'd like to use it also at home on an Intel PC... bye -- My eyes adapted to the darkness... finally I can see clearly now

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Self-interest February 2001