Squeak-dev December 2002

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173 participants
456 discussions

Regular- or context-free grammars with objects?
by Marcel Weiher 02 Dec '02

02 Dec '02

Hi folks, the code I've seen for parsing regular expressions or context-free grammars seems to pretty much assume that one is dealing with strings (or is it just my impression?). Is anybody aware of, for examle, object-based regex? How about diff? Thanks, Marcel -- Marcel Weiher Metaobject Software Technologies marcel(a)metaobject.com www.metaobject.com Metaprogramming for the Graphic Arts. HOM, IDEAs, MetaAd etc.

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Re: "Pattern Hatching"
by Daniel Vainsencher 02 Dec '02

02 Dec '02

I agree with this point and the wish for a higher abstraction (maybe one that allows one to instantiate a complete systems of interoperating objects), but I think patterns books in a way would still be useful. Once, because I think the most important aspect of the patterns books is that they present a very condensed source of design problems and their applicability. Not the solutions matter, but the problems. I think I didn't understand the tradeoffs implicit in reuse via inheritence, for example, until I read the GoF book. So assuming most programmers aren't born with this knowledge installed, awareness is already 90% of the distance to better code. Whether the book then points you at schemas for manual generation of a family of good solutions, or to a library solving it that's perfect and tested is a matter of degree. The large risk (coders that are amateur designers thinking they're inventing the wheel - for the first time!) is solved. Twice, because an important thing that makes artefacts live is that they be modular. Pattern languages aren't the answer, they are a crutch we should use to make this understanding concrete and widespread. Whether pattern books will still be useful as teaching aids when the knowledge is common is an open question. Christopher Alexanders books on patterns, including his early "Notes on the synthesis of form" address these topics and are very interesting and rich. Daniel Marcel Weiher <marcel(a)metaobject.com> wrote: > In an ideal world / programming language, > there would be no patterns books. > Marcel > > -- > Marcel Weiher Metaobject Software Technologies > marcel(a)metaobject.com www.metaobject.com > Metaprogramming for the Graphic Arts. HOM, IDEAs, MetaAd etc.

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[BUG]3.4-5125 FileDirectory>exists faulty?
by Tim Rowledge 02 Dec '02

02 Dec '02

I've just discovered a nasty side effect of the recent change to Filedirectory>exists (update 5114). The immediate effect is that is stops VMMakerTool from working on Acorn, but I can't see how it works properly at all. Given the latest CVS platform sources I have (a few days old) it looks to me that unix, win32 & Acorn all carefully handle _not_ returning an entry for the directory entry in prim dir_Lookup(). I can't tell about Mac since the way it works is so foreign to me. The new update seems to rely on the prim actually returning an entry with quite specific contents. I'm puzzled; obviously I could change the Acorn VM but a) it would break backwards compatability (big deal eh? nobody uses Acorn Squeak you think? Wrongo, dude, wrongo) b) since it looks like it is wrong on win32/unix, why change to match wrongness? I wonder when we will actually get a filename system that works cleanly... sigh. tim -- Tim Rowledge, tim(a)sumeru.stanford.edu, http://sumeru.stanford.edu/tim Useful Latin Phrases:- Fac ut vivas. = Get a life.

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Re: Uploading files to the minnow swiki?
by Karl Ramberg 02 Dec '02

02 Dec '02

Anthony Hannan wrote: > > Doug Way <dway(a)riskmetrics.com> wrote: > > > > I was just trying to upload a file to the Squeak Swiki on minnow, and I > > notice that all uploads are now password-protected. (I don't remember > > seeing any announcement on the list about this particular password > > protection.) > > There was an announcement a while ago by Mark Guzdial. The username is > 'squeak' and the password is 'viewpoints'. > > Cheers, > Anthony Maybe Cees could put it in the montly reminder that is sendt to list members ? Karl

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"Pattern Hatching"
by Richard A. O'Keefe 02 Dec '02

02 Dec '02

I've just been reading the book "Pattern Hatching: Design Patterns Applied" by John Vlissides, Addison-Wesley 1998, ISBN 0-201-43293-5. I have come away from this with two overwhelming impressions: (1) Here is a better than competent OO programmer, and C++ is fighting him every inch of the way. Example after example is basically "how do I design-hack a way around such-and-such a limitation of C++." I've always been fairly positive about patterns, and I've taught them to students. This book, by one of the GoF, made me wonder. The examples strike me as Heath Robinson-ish; is this because of pattern-think, or is it because of C++? It would be really illuminating to see some of his examples revisited by a better than competent Smalltalker, because I think you'd end up with a completely different set of patterns being applied, or the patterns would look different. (2) One of the chapters describes the "GENERATION GAP" pattern. The example is a visual interface builder, where you draw your interface and the tool then generates code. "Normally, you can't create a finished, nontrivial application automatically with one of these tools; you have to implement some functionality the old-fashioned way, by hand in a programming language." So GENERATION GAP helps you by doubling the number of classes. (Er, really.) But WHY do you have to develop part of the interface in one environment (the interface builder) and the rest in another environment? Why shouldn't "what to do when you are pressed" be something you can plug in *and test* in the interface builder? The answer appears to be "because the interface builder is generating C++" (see point 1 above) "and can't itself run the code it generates". POOF! An entire pattern disappears up its own fundament if your environment can represent code as data and can run dynamically generated code. I just wish I understood Morphic better. Smalltalk: back to the future????

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[BUG] SqueakMap Package Loader
by Nick Brown 02 Dec '02

02 Dec '02

Hi everyone. I finally got round to updating to 3.4 and trying out SqueakMap from within Squeak. However, I'm behind an http proxy, and it looks like I'm running into exactly the same problem as Alejandro Magistrello reported a while back. I'm running the latest version of 3.4a, with the latest win32 VM, I've double checked that Squeak is set up to use the proxy, and that access to port 8000 is ok. (1) From the world menu, I choose Open>>Package Loader. An error message tells me that no servers are responding. I modify TheWorldMenu(class)>>loadSqueakMap to bypass the check using the NetNameResolver (as detailed on minnow), and try again. (2) SqueakMap now loads, reports that no servers are available, and produces a DNU because of trying to load a package (presumably the SMLoader) with an empty map. (3) I comment out the first few lines of SMSqueakMap>>pingServer: and SMSqueakMap(class)>>pingServer:, again to bypass the NetNameResolver check. (as detailed in a posting by Göran on the list (4) Now I guess I need to try to download a map. I do the following in a workspace... SMSqueakMap allInstances first loadFull and I get a second log file in the sm subdirectory, of about 125K, so I think this has succeeded. (5) Next I opened a changesorter, and looked at the postscript for squeakmap-1_04, and selected the line... Cursor wait showWhile: [SMSqueakMap default loadUpdates installPackageWithId: ...etc and after a DoIt, the Package Loader appeared on screen. From here on, everything has worked ok, and I have been able to download and install packages fine. Rather than doing all of this, if I download squeakmap as a .cs.gz from the squeakmap website and file it in, it takes me straight to step 2, and the procedure from there on is the same. So it looks to me as if everything basically works - it's just that SqueakMap sometimes thinks that things aren't going to work and so doesn't try. Perhaps as a very simple solution, whenever SqueakMap complains that it can't find any servers, we should just have an option which says "I'm behind a proxy - try it anyway". I follow this list closely, and I'll be happy to try out any solutions or go into more detail about the problems in order to help get this fixed. Regards, Nick Brown

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Re: 70 packages on SqueakMap!
by Daniel Vainsencher 02 Dec '02

02 Dec '02

No, I'm proposing this only for installers, and that only as halfway measure for all those relatively simple packages that you can't install only for lacking the proper service. This is definitely NOT a proposed replacement to having configuration package types that encapsulate things like dependencies (though the idea of a reflective service that uses SM itself might be useful in other contexts too). I personally don't think we should model dependencies directly. If Goran's view of configurations is "I assert that the RB 1.2 works with PackageInfo 3.4", then my proposal is the agnostic "Loading PackageInfo 3.4 and then RB 1.2 and then ... is good". This could obviously be used to make sure both dependencies and proper scaffolding is installed before any specific package. This handles any depth dependencies in one configuration, and also allows composition of configurations to make packaging modular. Does this seem reasonable? Daniel Julian Fitzell <julian(a)beta4.com> wrote: > Daniel, > > Are you suggesting this only for installers or for all dependencies? > I'd hate to have to manually install the dependencies for a package. > You might easily have a few levels of depth in your dependencies. > > Julian > > Daniel Vainsencher wrote: > > I think I see what you mean. Let's see if I do: > > There's a conflict between expecting the services architecture to > > provide you with the correct installer for each package automatically, > > and between using any external dependency mechanism to represent this > > dependency. > > > > I think a good enough solution is - > > 1. The services architecture will not cause installation of anything, > > but it will help expose any packages to all services already installed > > in the image. > > 2. One of those services might use SqueakMap categories to find > > appropriate installers, and offer that option (example later). > > > > Example: > > I want to install the RB package. It has the category PackageType\SAR. > > All the SM services I have installed come forth and decide that they > > cannot install SARs, because none of them is SARInstaller. However, one > > of them is the Meta Installer (tm), and it detects that there's a > > package in SM that has the category PackageService\Installer\SAR (which > > happens to be called SARInstaller), and so offers to "install > > SARInstaller" on the menu. After the user chooses that, he now has > > SARInstaller, and will be able to install the RB. > > > > This takes care of the light weight scenario, where it should be > > straight forward for the user to install simple single packages, and > > would solve our current problem. > > > > Another scenario is the image configuration scenario, and I see nothing > > wrong in it loading first some installers, and then the needed packages. > > > > Daniel Vainsencher > > > > > > goran.hultgren(a)bluefish.se wrote: > > > >>Julian Fitzell <julian(a)beta4.com> wrote: > >> > >>>goran.hultgren(a)bluefish.se wrote: > >>> > >>>>Julian Fitzell <julian(a)beta4.com> wrote: > >>>>[SNIP] > >>>> > >>>> > >>>>>I didn't say SqueakMap depended on SARInstaller. I meant that packages > >>>>>that are packaged as SARs depend on SARInstaller. So when you try to > >>>>>install a SAR package and don't have SARInstaller, it will get installed > >>>>>first since it is a dependency. > >>>> > >>>> > >>>>Duh. Ok, sorry - didn't read careful enough. Yes, this would be neat. > >>>>But... hmmm. Interesting. It wouldn't work at all with the current > >>>>architecture - nor the one I am aiming for in 1.1. Hmmmm. > >>> > >>>I'm curious why it doesn't work with what you're planning. Isn't it > >>>just a simple matter of giving the package a dependency on the > >>>installer? Presumably all the dependencies are installed prior to the > >>>package itsself? > >>> > >>>I'm guessing I'm missing something obvious. > >> > >>Well, there are two issues at play here: > >> > >>1. The service architecture for finding the "actions" that you can do > >>with a package. Today each subclass of SMInstaller is queried if it > >>would like to handle package x and the first one that says yes gets to > >>supply "download" and/or "install". So if you don't have the installer > >>already installed - how does it raise its hand and say "Yes, I can > >>handle this package!". The future architecture that I have started > >>fiddling with collects services from registered "package handler > >>objects" instead - the services can be anything and there may be > >>services from multiple handlers. Anyway, the problem is still the same. > >> > >>2. When thinking more this is actually not a normal dependency. In the > >>planned SM 1.1+ people will register "package configurations" with the > >>dependencies for *using* package x. Not the dependencies for > >>*installing* it. I think these two things are different - for example - > >>the installer can easily be uninstalled after it has done its work - a > >>"normal" dependency can't be. > >> > >>So, what do we do? Well, after thinking about 20 seconds I am not sure I > >>would like to use "normal" dependencies for this. And it does feel like > >>overkill to introduce some other dependency structure just to handle > >>installation. I think perhaps we should be a bit more strict when it > >>comes to "Package type" - perhaps making it mandatory. And given this we > >>could perhaps map to at least a default installer package. I am not > >>sure.. > >> > >>I need to get a new revision of SM out - if you have any bright ideas > >>regarding the above I am listening. > >> > >>regards, Gsran > > > > > > > -- > julian(a)beta4.com > Beta4 Productions (http://www.beta4.com)

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Re: 70 packages on SqueakMap!
by Daniel Vainsencher 02 Dec '02

02 Dec '02

I think I see what you mean. Let's see if I do: There's a conflict between expecting the services architecture to provide you with the correct installer for each package automatically, and between using any external dependency mechanism to represent this dependency. I think a good enough solution is - 1. The services architecture will not cause installation of anything, but it will help expose any packages to all services already installed in the image. 2. One of those services might use SqueakMap categories to find appropriate installers, and offer that option (example later). Example: I want to install the RB package. It has the category PackageType\SAR. All the SM services I have installed come forth and decide that they cannot install SARs, because none of them is SARInstaller. However, one of them is the Meta Installer (tm), and it detects that there's a package in SM that has the category PackageService\Installer\SAR (which happens to be called SARInstaller), and so offers to "install SARInstaller" on the menu. After the user chooses that, he now has SARInstaller, and will be able to install the RB. This takes care of the light weight scenario, where it should be straight forward for the user to install simple single packages, and would solve our current problem. Another scenario is the image configuration scenario, and I see nothing wrong in it loading first some installers, and then the needed packages. Daniel Vainsencher goran.hultgren(a)bluefish.se wrote: > Julian Fitzell <julian(a)beta4.com> wrote: > > goran.hultgren(a)bluefish.se wrote: > > > Julian Fitzell <julian(a)beta4.com> wrote: > > > [SNIP] > > > > > >>I didn't say SqueakMap depended on SARInstaller. I meant that packages > > >>that are packaged as SARs depend on SARInstaller. So when you try to > > >>install a SAR package and don't have SARInstaller, it will get installed > > >>first since it is a dependency. > > > > > > > > > Duh. Ok, sorry - didn't read careful enough. Yes, this would be neat. > > > But... hmmm. Interesting. It wouldn't work at all with the current > > > architecture - nor the one I am aiming for in 1.1. Hmmmm. > > > > I'm curious why it doesn't work with what you're planning. Isn't it > > just a simple matter of giving the package a dependency on the > > installer? Presumably all the dependencies are installed prior to the > > package itsself? > > > > I'm guessing I'm missing something obvious. > > Well, there are two issues at play here: > > 1. The service architecture for finding the "actions" that you can do > with a package. Today each subclass of SMInstaller is queried if it > would like to handle package x and the first one that says yes gets to > supply "download" and/or "install". So if you don't have the installer > already installed - how does it raise its hand and say "Yes, I can > handle this package!". The future architecture that I have started > fiddling with collects services from registered "package handler > objects" instead - the services can be anything and there may be > services from multiple handlers. Anyway, the problem is still the same. > > 2. When thinking more this is actually not a normal dependency. In the > planned SM 1.1+ people will register "package configurations" with the > dependencies for *using* package x. Not the dependencies for > *installing* it. I think these two things are different - for example - > the installer can easily be uninstalled after it has done its work - a > "normal" dependency can't be. > > So, what do we do? Well, after thinking about 20 seconds I am not sure I > would like to use "normal" dependencies for this. And it does feel like > overkill to introduce some other dependency structure just to handle > installation. I think perhaps we should be a bit more strict when it > comes to "Package type" - perhaps making it mandatory. And given this we > could perhaps map to at least a default installer package. I am not > sure.. > > I need to get a new revision of SM out - if you have any bright ideas > regarding the above I am listening. > > regards, Gran

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[bug] SqueakMap walkback
by merlyn＠stonehenge.com 02 Dec '02

02 Dec '02

while trying to "download" the "refactoring browser for 3.2" Is SqueakMap not ready for prime time yet? or did I just hold my tongue wrong. This is the second or third thing I tried. MessageNotUnderstood: download 1 December 2002 4:17:16 pm VM: Mac OS - Squeak3.2gamma of 15 January 2002 [latest update: #4913] Squeak VM 3.4.0b1 Image: Squeak3.4alpha [latest update: #5125] UndefinedObject(Object)>>doesNotUnderstand: Receiver: nil Arguments and temporary variables: aMessage: a Message with selector: #download and arguments: #() Receiver's instance variables: nil [] in SMSqueakMapBrowser>>downloadPackage Arguments and temporary variables: installer: nil package: SMCard[Refactoring Browser for 3.2] BlockContext>>ensure: Receiver: [] in SMSqueakMapBrowser>>downloadPackage Arguments and temporary variables: aBlock: [] in CursorWithMask(Cursor)>>showWhile: returnValue: nil Receiver's instance variables: sender: BlockContext>>ensure: pc: 110 stackp: 0 nargs: 0 startpc: 101 home: SMSqueakMapBrowser>>downloadPackage CursorWithMask(Cursor)>>showWhile: Receiver: ((CursorWithMask extent: 16@16 depth: 1 fromArray: #( 2r0 2r11111111111111100000000...etc... Arguments and temporary variables: aBlock: [] in SMSqueakMapBrowser>>downloadPackage oldcursor: ((CursorWithMask extent: 16@16 depth: 1 fromArray: #( 2r0 2r1...etc... Receiver's instance variables: bits: a Bitmap of length 16 width: 16 height: 16 depth: 1 offset: -1@-1 maskForm: Form(16x16x1) --- The full stack --- UndefinedObject(Object)>>doesNotUnderstand: [] in SMSqueakMapBrowser>>downloadPackage BlockContext>>ensure: CursorWithMask(Cursor)>>showWhile: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - SMSqueakMapBrowser>>downloadPackage PluggableButtonMorph>>performAction [] in PluggableButtonMorph>>mouseUp: Array(SequenceableCollection)>>do: PluggableButtonMorph>>mouseUp: PluggableButtonMorph(Morph)>>handleMouseUp: MouseButtonEvent>>sentTo: PluggableButtonMorph(Morph)>>handleEvent: PluggableButtonMorph(Morph)>>handleFocusEvent: [] in HandMorph>>sendFocusEvent:to:clear: PasteUpMorph>>becomeActiveDuring: HandMorph>>sendFocusEvent:to:clear: HandMorph>>sendEvent:focus:clear: HandMorph>>sendMouseEvent: HandMorph>>handleEvent: HandMorph>>processEvents [] in WorldState>>doOneCycleNowFor: Array(SequenceableCollection)>>do: WorldState>>handsDo: WorldState>>doOneCycleNowFor: WorldState>>doOneCycleFor: PasteUpMorph>>doOneCycle [] in Project class>>spawnNewProcess [] in BlockContext>>newProcess -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 <merlyn(a)stonehenge.com> <URL:http://www.stonehenge.com/merlyn/> Perl/Unix/security consulting, Technical writing, Comedy, etc. etc. See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl training!

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Morphic Wrappers on SqueakMap?
by yampa＠mindspring.com 02 Dec '02

02 Dec '02

Is anyone working on putting morphic wrappers on SqueakMap? I'd like to put a package onto SqueakMap soon that depends on it.

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