Squeak-dev August 1999

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134 participants
348 discussions

Re: Eliminating assignments and variable syntax (accessors)
by Hans-Martin Mosner 03 Aug '99

03 Aug '99

Marcel Weiher wrote: > The basic idea is to replace the binding of names to variables with > messaging. > > In order to accomplish this, the notion of messaging with implicit > targets and a lookup chain is introduced. For example, messages to > self do not need to be prefixed with 'self'. > > self hi. -> hi. > self hi:newHi. -> hi:newHi. .... > I think this sketch addresses most of the issues raised on both > sides of the debate (and sounds suspiciously like SELF). This is the (syntactical) core of SELF, and the reason it's got this name. Of course, complete SELF is a lot more. Have you ever noticed how methods and their activations correspond to classes and their instances? If you take this a little further, temporaries could be just the instance variables of these 'method-classes'. It's somewhat funny how this seems to ring the bell 'Simula' in my head :-) In that precursor of Smalltalk, objects were a somewhat accidental by-product of the coroutine feature, that is, an object was created by a function that just retained its activation, if I remember correctly. But I may be totally wrong on this one, it's been more than 15 years since that... Hans-Martin (wish I had a better memory)

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Re: Please help: Recovering Swiki from "crash"?
by Lex Spoon 03 Aug '99

03 Aug '99

If look in the actual Swiki directory, there will be a bunch of files named 1, 2, 3, .... There is one file per page, an if you look in the files, you will see all previous versions of each page are in there. In the worst case, you could go in there with a text editor and cut and paste your things out. As for why it happens, how do you restart your Swiki? If you restart it with a "restoreFrom:" command, then it will read in all the old files. If you go through the initial creation methods again, however, it will start a new Swiki and forget about all its pages.... If I'm not mistaken, the proper command would look like: SwikiAction restore: 'swikiname'. (Assuming you have set up ServerAction>>serverDirectory already). I'm sure someone will correct this if I'm wrong :) Lex

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RE: Eliminating assignments and variable syntax (accessors)
by Jarvis, Robert P. 03 Aug '99

03 Aug '99

Re: keep the receiver in message patterns - YES, PLEASE!!!!! Re: getting rid of assignments: In your example "var" is not part of self. How about using something like "thisContext" instead, which would be more descriptive of the owner of "var"? <ramble> To this point I haven't seen a proposal for eliminating assignments which made me want to leap to my feet and shout "Amen!". I feel a bit like a moth, drawn to the flame of functional programming, but I dislike the functional community's obsession with static type checking. The elimination of state from programming seems to confer some real advantages - but without state what is an object? </ramble> Bob Jarvis The Timken Company > -----Original Message----- > From: Stephen Pope [SMTP:stp@create.ucsb.edu] > Sent: Monday, August 02, 1999 5:09 PM > To: squeak(a)cs.uiuc.edu > Subject: Re: Eliminating assignments and variable syntax (accessors) > > This is getting a bit involved, but I have another idea. First, two > principles: > > 1) We should keep the receiver in message patterns. (I'm against > abbreviated message-sends.) > > 2) We want to get rid of assignment. (It's always a hack, except if you > make it a function as in LISP, or do away with it, as in functional > languages.) > > Solution: If we had the notion of "implicit accessors," we could write, > > | var | > self var: 42. > Transcript show: self var printString; cr. > > The code that implements doesNotUnderstand (or, even better, handles the > exception MessageNotUnderstood) could then look in the local scope to > see if there's a variable named "var" and handle the assignment and > reference as "implicit accessing" -- this way it appears that we have > accessors even for local temp. vars. > > (This is very similar to several other schemes that use > doesNotUnderstand for "generic behavior" or property list objects.) > > If we did it this way, we could do away with all accessors (except for > the speed hit we'd take passing though doesNotUnderstand on IV > accesses). > > stp > > -- > > Stephen Travis Pope -- http://www.create.ucsb.edu/~stp > stp(a)create.ucsb.edu -- stp9(a)cornell.edu

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Please help: Recovering Swiki from "crash"?
by Robb Shecter 03 Aug '99

03 Aug '99

Hi, I'm afraid I might have lost 2 weeks of work that I had in a Swiki: Squeak was doing OK, but due to another problem, my X-Window session restarted, killing Squeak along with it. Now, browsing through the Swiki, none of my recent updates are there. I did find the log.txt file, and it looks like all my recent changes are in there. The log file is encoded though, in some kind of format. So - anybody know how to bring the Swiki back up to date with the changes from the log? (Or, just getting the plaintext back out of the log?) Thanks, Robb

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[squeak newbie] window problem
by Martin Brown 03 Aug '99

03 Aug '99

I just installed squeak (Linux). While fooling around looking at the initial demo windows, I've run into a problem which doesn't seem to be covered in the online (web) docs. (My terms might be incorrect) If I click on one of those title bar only collapsed windows , it expands into a normal window. If I double click on the title bar, it maximizes to cover the squeak screen (?) completely, and it's title bar disappears. How do I de-maximize it? None of the menu items does it, and I have to exit squeak and start over. ---- Is there, or will there be, a way to run squeak using a native (to Linux/UNIX) GUI/toolkit (X, motif)? If not are there any ST's outthere that are free, at least for non-commercial purposes, and currently use the native GUI/toolkit? Thanx. - Martin J. Brown, Jr. - - BEAUDESIGN.COM -

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RE: OpenGL (again?)
by Raab, Andreas 03 Aug '99

03 Aug '99

Shane, Richard, I'm just curious: Are you really talking about having OpenGL in Squeak or are you talking about a high speed immediate mode interface for 3D rendering - which might not necessarily use OpenGL?! Though I appreciate the power and simplicity of OpenGL (as opposed to say Direct3D) I *am* actually considering different versions of a 3D accellerated backends - depending on the platform and what is fastest and best supported on it. The abstraction layer (which has to be introduced anyways to actually interface with OpenGL or anything else) could give you the feeling of something like OpenGL (and the B3DRenderEngine interface is heavily influenced by OpenGL) without actually *using* OpenGL. The entire point of using OpenGL would be to have a uniquely defined (and actually verified; see the OpenGL conformance tests) behavior across all implementations. But while this is a nice thing to have I do not really care about whether 20 out of a million pixels have a slightly different color (don't laugh - if you look at the conformance tests run with Mesa 3.0 that's where they failed and they *do* work on it). Andreas -- +===== Andreas Raab ========= (andreasr(a)wdi.disney.com) ==+ | Walt Disney Imagineering Phone: +1 818 544 5016 I I Glendale, CA Fax: +1 818 544 4544 I +======< http://isgwww.cs.uni-magdeburg.de/~raab >========+ > ---------- > From: Shane Hayes > Reply To: squeak(a)cs.uiuc.edu > Sent: Monday, August 2, 1999 7:13 PM > To: squeak(a)cs.uiuc.edu > Cc: recipient list not shown > Subject: Re: OpenGL (again?) > > I hope someone does. Right now I am working at learning fuzzy logic and > implementing it in Squeak. Once I get some helicopter flight control > software > written, I would like to create visual representations of the flying using > OpenGL. > > "Richard L. Peskin" wrote: > > > Is anyone looking at porting the Jun301 OpenGL interfaces to Squeak. I > > downloaded these for both Mac and Linux, and this is an impressive > addition > > to Smalltalk, albeit only for VW. It would be a great addition to > Squeak. > > --dick peskin > > > > ================================= > > R. L. Peskin, Rutgers Univ. > > ;<peskin(a)caip.rutgers.edu>;<http://www.caip.rutgers.edu/~peskin> > > RLP Consulting <rlpcon(a)sover.net>; <http://www.sover.net/~rlpcon> > > >

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Re: [SqT][BUG?] Can't debug after updating to 2.5test
by Bob Arning 03 Aug '99

03 Aug '99

On Mon, 2 Aug 1999 23:48:24 +0200 Marcel Weiher <marcel(a)system.de> wrote: >After fetching the test pilot updates, trying to debug gets me the error > >Message not understood "classOf:" > >The culprit is > >Inspector>>objectClass > ^ObjectInspector classOf:object. > >In my system, ObjectInspector is not defined and there isn't a >single implementation of #classOf: either. > >Marcel Curious - I have an updated 2.5 test system and can't find either reference. What change set did the offending code come in? Cheers, Bob

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OpenGL (again?)
by Richard L. Peskin 03 Aug '99

03 Aug '99

Is anyone looking at porting the Jun301 OpenGL interfaces to Squeak. I downloaded these for both Mac and Linux, and this is an impressive addition to Smalltalk, albeit only for VW. It would be a great addition to Squeak. --dick peskin ================================= R. L. Peskin, Rutgers Univ. ;<peskin(a)caip.rutgers.edu>;<http://www.caip.rutgers.edu/~peskin> RLP Consulting <rlpcon(a)sover.net>; <http://www.sover.net/~rlpcon>

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Browser Plugin
by Alexander Lazarevic 03 Aug '99

03 Aug '99

Hi! I used the source files from Andreas Browser Plugin for Win32 systems and wrote a version for unix. (Ok, nothing the squeak world was desperately waiting for, but hey ...) To be honest I have to say, that I just compiled it here on my linux box, but I think it should compile on other unix systems as well. The plugin is far from perfect (I'm no X11pert) and should be considered experimental. If somebody wants to have a look at it: <http://www.cs.uni-magdeburg.de/~lazarevi/squeak/squeak_plugin.html> Alex. -- ------ Alexander Lazarevic ------------------------------------------------ -- Otto-von-Guericke-Universitaet mailto: Alexander(a)Lazarevic.de -- -- Computational Visualistics http://www.cs.uni-magdeburg.de/~lazarevi --

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Accessors
by Andres Valloud 03 Aug '99

03 Aug '99

Hi. I think that wether anObject implements its messages using accessors or just referencing variables on the fly is the same, provided that anObject is properly built and designed. I also think that even more important that the implementation is the protocol design, in which the accessors are included. Since Smalltalk doesn't enforce message privacy (something like #willNotAnswer: aMessage), marking accessors as private does not really exclude them from the protocol. Assuming for a minute that instance variables should have read/write accessors, in the Interval case this would allow mutators, which is more than accessors. I don't think mutators are desirable for Interval, although I think accessors are fine. So, the read/write pair is not always desirable. Some other times, even reading accessors are not desirable. For instance, consider a BinaryTree. There are many ways to implement a BinaryTree. Then, BinaryTree is the abstract class and its subclasses implement the BinaryTree protocol in different ways. BinaryTree could define an instance variable named tree, in which every subclass would store the nodes, or the information of the nodes, or whatever. Access to this local variable should not be allowed, not even for reading, if the coherency of the BinaryTree is to be ensured (aTree nodes become: nil). The only way to do this is by using immediate references to the tree instance variable. For Trees, I have built an abstract class named AbstractTree, with subclasses implementing its most basic and primitive protocol. The rest of the protocol is implemented at AbstractTree. The remaining 14 methods, 5 of which are private, do all the low level hard work like adding/deleting/finding nodes, tree pruning and grafting, and tree maintenance. Some trees store nodes with linking information, some others like one kind of BinaryTree just store the nodes' information. The only methods that use immediate access to the instance variable are the five private methods that must be implemented for each concrete subclass of AbstractTree. In short, I think that accessors/mutators depend first on the protocol design. In addition, I think that if each object is the only entity that can see its instance variables, it is automatically entitled to make use of that knowledge. Unless design dictates against it, as in lazy initialization or any other mechanism, I think that plain accessors that are just ^instVar are somewhat redundant once the object protocol implementation model is clear. Andres.

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