Squeak-dev November 1998

squeak-dev@lists.squeakfoundation.org

128 participants
265 discussions

|[Fwd: http://www.dm.uba.ar/MathMorphs]
by Gerardo Richarte 03 Nov '98

03 Nov '98

If somebody is interested in Squeak+Teching+Math here is something you may want to see: Leandro Caniglia wrote: > We have good news: > > During the week end I was working on our site. The site was moved, > reorganized, updated and extended. New projects have been included and the > old ones have now new versions for Squeak 2.2 (BookMorphs, ClassOrganizer, > etc. have changed since 2.2). So, almost everything is new, the new files > and the old too. > > Please, if somebody out there has any problem with the site, please, let me > know. Now I have direct ftp access to the directories. > > Saludos, > Leandro > ----- > "Although it is quite possible to write programs which depend on the byte > size, this is an illegal act which will not be tolerated" Donald E. Knuth, > The Art of Computer Programming, Vol 1. Too by lucky is good! Good Bye! Richie++

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Regenerating the VM
by Luciano 03 Nov '98

03 Nov '98

I updated my image and regenerated the VM (in Linux) in order to make finalization and pluggable primitives work, but I've got into troubles... the new VM did not work properly. This is what happens: if I type a char, nothing shows, until I type other char or move the mouse. What is happening? Did someone noticed this behavior before? Luciano.-

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Re: some not-so-random questions
by lex＠cc.gatech.edu 03 Nov '98

03 Nov '98

Andreas Raab <raab(a)isgnw.CS.Uni-Magdeburg.De> wrote: > > > 2) What is the default memory allocation then, if none is specified > > explicitly? > > 16 MB - that's an average choice between common memory sizes and the > amount of memory you need to have fun with the system. Oh, but don't > expect Squeak to physically use the amount of memory - we're on Windows, > we *do* have dynamic virtual memory management ;-)=) > Yeah, but doesn't Squeak cycle through all its free memory over and over as it runs? So if you allocate 40 megs, and 10 megs of that is old, then all 30 megs of the "free" space will be cycled through periodically. If you only have 32 megs of RAM on your machine, then that 30 megs of free won't fit and it should be paged out and in over and over and over again. It's not just the least-common memory pages that will be paged out, because all the pages are being used. But it's fixable! Squeak just needs to garbage collect more often when there is a lot of free space, so that it doesn't need to get near the top of its memory allocation. Then, the top of Squeak's memory can usufelly page out and stay out. It would be nice, and I think it would work, but I don't know enough about how the memory management works to actually implement it.... Lex

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Re: Units package (was Method names)
by Stan Heckman 03 Nov '98

03 Nov '98

I too am interested in a units package for squeak. I have implemented a units package in another language (Mathematica) that handles Sam's "general case which ends up with composite units like furlongs per cubic fortnight per dyne centimeter." I agree with Sam that "you then need an algebraic system with mappings for unit definitions (dyne cm = erg, etc) so these composite units could recognize whether they were compatible or not and if the units could be reduced or mapped to another unit." The only two "mathematical" functions I used from Mathematica to do this were one that told me whether a set of vectors was linearly independent, and one that returned combinations from a set, taken N at a time. I know squeak already has a function for returning combinations N at a time, so all we need is the linear independence checker. Can someone point me to a linear algebra library for squeak? Things that gave me grief before, and that would be good to do more simply this time, are non-absolute temperatures, lists and tensors, automatic unit simplification and functions other than (+ - * /). What's the problem with non-absolute temperatures? Well, when I say that I heated my dinner from 40 Fahrenheit to 400 Fahrenheit, I would like to keep the same units, and describe the temperature difference as 360 Fahrenheit. If I want the heat put into dinner, I multiply dinner's mass and heat capacity by 360. But if I let the oven cool 40 degrees, and then want to compute the density of the air using the ideal gas law, I want not 360, but 360 + 459.67. As human beings we figure out the right thing to do in each case from context, but I don't think Squeak can be that smart. The resolution I've used before is to never use non-absolute temperature scales for temperature differences, only for temperatures. The Mathematica units package handles this automatically; I doubt that feature was really worth the complexity it cost. What's the problem with lists? One must either keep the units once per list, or once per element of the list. No matter which one chooses, half the time one wishes it were the other way. My bias is to keep the units of homogeneous lists only once per list, because this preserves the information that the list is dimensionally homogeneous, and without this I found my code became cluttered with checks to see whether a list was homogeneous. What's the problem with automatic simplification? Well, when I divide newtons per ampere squared by farads per meter, it's a very good bet that I want to see units of ohms squared. But when I divide miles by hours, I probably don't want to see this simplified to knots. Humans have a lot of heuristics for this, learned in years of classwork, and learned differently in different disciplines. I found that I could do a pretty good job of reproducing my own heuristics by simplifying only if I could reduce the total number of base units required, not introduce any fractional powers, and I restricted my base units to the set of units I started with plus joule, watt, pascal, newton, coulomb, volt, ohm, farad, henry, tesla, weber, and siemens. Using units in the original expression before the units above will usually keep absorbed dose in rads, instead of converting it to pascals. What's the problem with functions other than +, -, *, and /? The problem is that there are so many of them. :-) In the Mathematica package, I kept encountering functions that should work with dimensional quantities but didn't. See the functions section on the web page. If someone can figure out any way to avoid the same proliferation of tiny methods in the Squeak units package, that would be a very important contribution. An HTML version of my (Mathematica) units package is available at http://stanheckman.com/a/98h/glimpsedotter/html/PhysicalUnits.html The (brute force) automatic simplification section might be interesting to someone implementing similar functionality in Squeak. -- Stan

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Re: Re: Method names
by Alan Kay 03 Nov '98

03 Nov '98

Andres -- I am on your side in spirit. Smalltalk-72 allowed one to put a grammar on each class, and this allowed quite a bit of syntactic extension. The result was good until we tried to share code -- then we found it difficult to read each other's "perfectly obvious syntaxes". Dan Ingalls did a cool thing when he designed Smalltalk-76: make an operator/keyword grammar that all can read regardless of where the code was written. At the time I made your suggestion that the compiler could know about other forms, and the very good answer was that this could make it very difficult again to write code that would not generate lots of syntax conflicts. The best solution to this problem that I have seen is CodeWorks by Mark Lentzner, in which a little more flexibility is allowed in where the keywords can go, but in which the language is still unambiguous to read and write. Better readability is one of the main issues we are addressing over the next months and year, so perhaps some of your hopes will be realized ... Cheers, Alan ------- At 1:37 AM -0000 11/3/98, sqrmax(a)cvtci.com.ar wrote: >Hi. > >>[Incidentally, that would be (aBitStream next: (40 bits))] >>Knowing what method selectors exist in the image would not be enough. If >>there existed #next:bits, #next:, and #bits, you would not be able to tell >>which interpretation of "<expr1> next: <expr2> bits" was the proper one >>without knowing (and you can't) the types of the expression results. >What's >>even worse, in a dynamic environment where selectors come and go, adding >or >>removing a selector would mean potentially changing the parse tree of some >>of the already compiled methods. > >What I also wanted was a way to tell the compiler that the method indeed is >#next:bits, and then no ambiguity can happen (I guess). > >Andres.

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FormView and StandardSystemView
by ohshima＠is.titech.ac.jp 03 Nov '98

03 Nov '98

Hi. I'm trying to make an application view that contains an instance of FormView and other views. But I found a problem. Please evaluate the following code: f _ Form fromUser. f edit. The FormEditor is supposed to be un-resizable, but when I touch the right- (or left-) bottom corner of the window by mouse, the window shrinks and the form gets scaled. It seems to me that the handling of the labelFrame of StandardSystemView is wrong for the calculation of the extent of the "topView". What I want to do is to display a form with its exact size and to prevent it getting scaled. The other examples I looked are also trying to do this by setting minimumSize and maximumSize same, but the calculation of the size seems very complecated. Is there much decent way to do this? I checked this on Squeak 2.2 on UNIX and Windows95. Thank you. OHSHIMA Yoshiki Dept. of Mathematical and Computing Sciences Tokyo Institute of Technology

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A bit of header
by sqrmax＠cvtci.com.ar 03 Nov '98

03 Nov '98

Hi. What do you think about using one of the unused bits in the image header as a flag to tell if the image was properly closed or not? This would allow the VM to warn the user if he/she tries to open a not closed image. An example of this is to open an image twice, which can result in a damaged changes file. Andres.

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Float>>#rounded
by sqrmax＠cvtci.com.ar 03 Nov '98

03 Nov '98

Hi. Why isn't Float>>#rounded implemented as a primitive? I think most FPUs have this nice feature... Andres.

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Toward the next release...
by Dan Ingalls 03 Nov '98

03 Nov '98

Folks - I thought it might be useful to let you all know about plans for the next release. I'm shooting for either just before Thanksgiving (nov 23rd), or possibly the week before, if everything is ready. What will this include? 1. Well, to begin with, all the updates that are out now, and VMs that support the new primitives (pluggable primitives and weak arrays). 2. Also the wavelet transform will be included, and a bunch of work Scott Wallace is doing on Scripting and viewers in morphic. 3. I am talking with Travis Griggs about folding in his numeric coercion improvements. This is like deja vu for me, since I was the one who put double-dispatching into ST-80 before the version 2 release went out from Xerox waaaaay back then. 4. Then there will be a first pass at Squeak Pages - an architecture that began with John Malone's WebBook project, and that has been carried through to a first level of completion by Ted Kaehler. It basically maps a morphic world onto a web page in a manner that lets you build vast amounts of morphic content that can be non-resident so you don't need a huge image, and that can be shared like everything else on the web. Refinements to properly support active objects in those worlds are in porgress. 5. Finally is Andreas Raab's as-yet-to-be-named resolution-independent outline-based anti-aliasing 2-D rendering engine (maybe we'll call it "hyphen" ;-). This is built on primitives with the speed and generality of BitBlt, but with other wonderful properties. This first release will only provide the primitive functionality, but it will enable many experiments. It is my hope that we will be able to slide this in under all the existing warpBlt hacks, and end up with a thing of real beauty. The design is also intended to support nice 3-D... If you have other features that you feel should be included at this time, please send me a message. I will try to assemble a beta release about a week before the target date of issue. - Dan

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Porting squeak to the Alpha
by Rob McIlhargie 03 Nov '98

03 Nov '98

Hi Everyone, I'm trying to compile the Squeak v2.2 VM on Alpha GNU/Linux(Linux on the DEC Alpha microprocessor), but it won't run at all. I've made the appropriate changes to the sqConfig.h and GNUmakefile.conf and sqXwindow.c. It compiles with a lot of warnings. It won't run because time_t on a 64-bit architeture is greater than 4. I commented out the check for sizeof(time_t)!= 4 and now I get a core dump. It looks like this is caused by converting pointers to integers, which causes a loss of precision since pointers are 64 bits and integers are 32 bits. Does anyone know how this code runs on Alpha OSF/1? Thanks in advance. -- ------------------------------------------------------------------------------ Rob. | http://www.smart.net/~rmcilhar/ rmcilhar(a)smart.net | rmcilhar(a)sanctuary.smart.net | POWERED by LINUX!!!! ------------------------------------------------------------------------------

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