Self-interest November 1995

self-interest@lists.selflanguage.org

21 participants
34 discussions

Re: undo
by Jecel Mattos de Assumpcao Jr. 07 Nov '95

07 Nov '95

On Thu, 2 Nov 1995 09:07:28 +0000, dib(a)signal.dra.hmg.gb (David Bruce) wrote: > [ transporting clones from a read-only past. Linear rather than > "branching times" ] > > Since the simulation is partitioned into objects, what usually happens > is that each object has a linear time, though of course the overall > emergent effect is branching as you say. I thought that the way parallel simulations worked was to have each object forge ahead as if there won't be any changes in its inputs. If a change does come along, it would back up to that point and rerun the simulation again (killing the "wrong branch"). A lot like the "speculative execution" that goes on in modern CPUs. > Either way, making the past read-only does make life a *lot* easier. Except for Star Trek script writers :-) > [ last N versions - too much memory ] > > The memory overhead can be a real nuisance. > (Even when you've got sufficient memory we've found that caches tend > to perform less effectively, and that can be quite significant.) As I said before, I am hoping to find some good solution to this problem. Meanwhile, a not very good one it to have only the last version of each object and a "reverse write log" of the current session. Each write to memory adds the address and the previous content to the log. Playing the log backwards allows you to recover any state in the current session. This log will probably prove to be too large to be practical (note that it can also be used for garbage collection, which is why I said these things are best done in the virtual machine) and would be cleared when you logout, so the past sessions would be lost. > There has been some work on reversible systems that don't depend on > storing additional versions but on reversible computations; this might > then be of some interest. One recent example is Henry Baker's > "NREVERSAL of Fortune --- The Thermodynamics of Garbage Collection" in > the 1992 International Workshop on Memory Management. Thanks for the tip! I also found this related paper: "Thermodynamics and Garbage Collection" Henry G, Baker ACM Sigplan Notices 29, 4 (April 1994), pp. 58-63 I could be wrong, but I think that the assignment primitive makes Self computations very non-reversible. -- Jecel

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Re: Hello, world!
by Randall.Smith＠Eng.Sun.COM 07 Nov '95

07 Nov '95

Amazing that this worked exactly as advertised! We have to stick in our contrib area! The way we draw shadows is incorrect;y designed in Self 4.0...that should be easy to override for cases eactly like this, and it isn't. Ass to the other problem (#1, clicking on the hidden part of a submorph) simply add a slot allowSubmorphsToGetEvent: evt = (globalBaseBounds includes: evt cursorPoint) and you're done! Thanks, very nice! --Randy > From Michael.Huebner(a)PrakInf.TU-Ilmenau.DE Tue Nov 7 10:40 PST 1995 > Date: Tue, 7 Nov 1995 17:39:59 --100 > From: Michael.Huebner(a)PrakInf.TU-Ilmenau.DE (Huebner) > To: SELF-INTEREST(a)SELF.sunlabs.com > Subject: Re: Hello, world! > X-Sun-Charset: US-ASCII > Content-Type: text > Content-Length: 8789 > > > Here is my module 'scroll' for a simple scrollMorph (in globals>ui2>...>Basic>). > Put it in a file and say '_RunScript' to the filename in Self (Is there a better > way to fileIn a module?) > It is a very raw hack to look what happens, no quality at all. > You have to get a copy of the sliderMorph (0.0 .. 100.0) and set the target of it > to your copy of the scrollMorph. > The selector that is to be sent from the sliderMorph to your scrollMorph has to be > set by hand in your sliderMorph to 'scrollY:'. Don't forget the colon at the end! > > To bring another morph into your scrollMorph place the morph in the position > where it should be when the slider is up and use the 'Embed in Morph Below' feature. > A good scrollee for the test is the green 'Welcome to Self 4.0' morph. > > > The problems that occur are > 1) when you click on the region with the hidden part of the embedded morph > the scrollMorph is selected > (this happens only after you selected the scrollMorph at most once) > 2) when moving the scrollMorph, the shadowing of the embedded morph is not clipped > on the boundaries of the scrollMorph > > This behavior is not easy to change. > > Michael > > ----------------- cut here -------------------------------------------------------- > > '$Revision:$' > ' > Copyright 1992, 1993, 1994, 1995 Sun Microsystems, Inc. and Stanford University. > See the LICENSE file for license information. > ' > > > '-- Module body' > > bootstrap addSlotsTo: bootstrap stub -> 'globals' -> 'modules' -> () From: ( | { > 'ModuleInfo: Module: scroll InitialContents: FollowSlot' > > scroll = bootstrap define: bootstrap stub -> 'globals' -> 'modules' -> 'scroll' -> () ToBe: bootstrap addSlotsTo: ( > bootstrap remove: 'comment' From: > bootstrap remove: 'directory' From: > bootstrap remove: 'fileInTimeString' From: > bootstrap remove: 'postFileIn' From: > bootstrap remove: 'revision' From: > bootstrap remove: 'subpartNames' From: > globals modules init copy ) From: bootstrap setObjectAnnotationOf: bootstrap stub -> 'globals' -> 'modules' -> 'scroll' -> () From: ( | > {} = 'ModuleInfo: Creator: globals modules scroll. > > CopyDowns: > globals modules init. copy > SlotsToOmit: comment directory fileInTimeString postFileIn revision subpartNames. > > \x7fIsComplete: '. > | ) . > } | ) > > bootstrap addSlotsTo: bootstrap stub -> 'globals' -> 'modules' -> 'scroll' -> () From: ( | { > 'ModuleInfo: Module: scroll InitialContents: FollowSlot\x7fVisibility: public' > > comment <- ''. > } | ) > > bootstrap addSlotsTo: bootstrap stub -> 'globals' -> 'modules' -> 'scroll' -> () From: ( | { > 'ModuleInfo: Module: scroll InitialContents: FollowSlot\x7fVisibility: public' > > directory <- 'applications'. > } | ) > > bootstrap addSlotsTo: bootstrap stub -> 'globals' -> 'modules' -> 'scroll' -> () From: ( | { > 'ModuleInfo: Module: scroll InitialContents: InitializeToExpression: (_CurrentTimeString)\x7fVisibility: public' > > fileInTimeString <- _CurrentTimeString. > } | ) > > bootstrap addSlotsTo: bootstrap stub -> 'globals' -> 'modules' -> 'scroll' -> () From: ( | { > 'ModuleInfo: Module: scroll InitialContents: FollowSlot' > > postFileIn = ( | > | > transporter moduleDictionary resetFillingSemaphore. > snapshotAction addSchedulerInitialMessage: > message copy receiver: transporter moduleDictionary > Selector: 'resetFillingSemaphore'. > resend.postFileIn). > } | ) > > bootstrap addSlotsTo: bootstrap stub -> 'globals' -> 'modules' -> 'scroll' -> () From: ( | { > 'ModuleInfo: Module: scroll InitialContents: FollowSlot\x7fVisibility: public' > > revision <- '$Revision:$'. > } | ) > > bootstrap addSlotsTo: bootstrap stub -> 'globals' -> 'modules' -> 'scroll' -> () From: ( | { > 'ModuleInfo: Module: scroll InitialContents: FollowSlot\x7fVisibility: public' > > subpartNames <- ''. > } | ) > > bootstrap addSlotsTo: bootstrap stub -> 'globals' -> () From: ( | { > 'Category: ui2\x7fCategory: System\x7fCategory: Morphs\x7fCategory: Basic\x7fModuleInfo: Module: scroll InitialContents: FollowSlot\x7fVisibility: public' > > scrollMorph = bootstrap define: bootstrap stub -> 'globals' -> 'scrollMorph' -> () ToBe: bootstrap addSlotsTo: ( > bootstrap remove: 'parent' From: > bootstrap remove: 'prototype' From: > globals morph copyRemoveAllMorphs ) From: bootstrap setObjectAnnotationOf: bootstrap stub -> 'globals' -> 'scrollMorph' -> () From: ( | > {} = 'ModuleInfo: Creator: globals scrollMorph. > > CopyDowns: > globals morph. copyRemoveAllMorphs > SlotsToOmit: parent prototype. > > \x7fIsComplete: '. > | ) . > } | ) > > bootstrap addSlotsTo: bootstrap stub -> 'traits' -> () From: ( | { > 'Category: ui2\x7fCategory: System\x7fCategory: Morphs\x7fCategory: Basic\x7fModuleInfo: Module: scroll InitialContents: FollowSlot\x7fVisibility: public' > > scrollMorph = bootstrap setObjectAnnotationOf: bootstrap stub -> 'traits' -> 'scrollMorph' -> () From: ( | > {} = 'ModuleInfo: Creator: traits scrollMorph. > '. > | ) . > } | ) > > bootstrap addSlotsTo: bootstrap stub -> 'globals' -> 'scrollMorph' -> () From: ( | { > 'ModuleInfo: Module: scroll InitialContents: FollowSlot\x7fVisibility: public' > > parent* = bootstrap stub -> 'traits' -> 'scrollMorph' -> (). > } | ) > > bootstrap addSlotsTo: bootstrap stub -> 'globals' -> 'scrollMorph' -> () From: ( | { > 'Category: filing out\x7fModuleInfo: Module: scroll InitialContents: FollowSlot\x7fVisibility: public' > > prototype = ( | > | scrollMorph). > } | ) > > bootstrap addSlotsTo: bootstrap stub -> 'globals' -> 'scrollMorph' -> () From: ( | { > 'Category: clipping\x7fModuleInfo: Module: scroll InitialContents: InitializeToExpression: (0)' > > x_off <- 0. > } | ) > > bootstrap addSlotsTo: bootstrap stub -> 'globals' -> 'scrollMorph' -> () From: ( | { > 'Category: clipping\x7fModuleInfo: Module: scroll InitialContents: InitializeToExpression: (0)' > > y_off <- 0. > } | ) > > bootstrap addSlotsTo: bootstrap stub -> 'traits' -> 'scrollMorph' -> () From: ( | { > 'Category: contents handling\x7fModuleInfo: Module: scroll InitialContents: FollowSlot' > > contents = ( | > | > 0 = morphCount > ifTrue: [^morph]. > ^firstMorph). > } | ) > > bootstrap addSlotsTo: bootstrap stub -> 'traits' -> 'scrollMorph' -> () From: ( | { > 'ModuleInfo: Module: scroll InitialContents: FollowSlot' > > drawOn: aCanvas = ( | > | > baseDrawOn: aCanvas. > 0 = morphCount > ifFalse: [aCanvas withClip: baseBounds Do: > [|c| c: (aCanvas copyOffset: position + (x_off @ y_off)). > morphsReverseDo: [| :m | m drawOn: c]]]. > self). > } | ) > > bootstrap addSlotsTo: bootstrap stub -> 'traits' -> 'scrollMorph' -> () From: ( | { > 'Category: contents handling\x7fModuleInfo: Module: scroll InitialContents: FollowSlot' > > noStickOuts = bootstrap stub -> 'globals' -> 'true' -> (). > } | ) > > bootstrap addSlotsTo: bootstrap stub -> 'traits' -> 'scrollMorph' -> () From: ( | { > 'Category: contents handling\x7fModuleInfo: Module: scroll InitialContents: FollowSlot' > > noStickOuts: arg = ( | > | self). > } | ) > > bootstrap addSlotsTo: bootstrap stub -> 'traits' -> 'scrollMorph' -> () From: ( | { > 'ModuleInfo: Module: scroll InitialContents: FollowSlot' > > parent* = bootstrap stub -> 'traits' -> 'morph' -> (). > } | ) > > bootstrap addSlotsTo: bootstrap stub -> 'traits' -> 'scrollMorph' -> () From: ( | { > 'Category: scrolling\x7fModuleInfo: Module: scroll InitialContents: FollowSlot' > > scrollY: value = ( | > origExtent. > clipExtent. > spaceToScroll. > new_y_off <- 0. > | > "called when using the scrollbar, value in [0.0, 100.0]" > origExtent: contents height. > clipExtent: baseBounds height. > spaceToScroll: origExtent - clipExtent. > spaceToScroll > 0 ifTrue: [ > new_y_off: (((value/ 100) - 1) * spaceToScroll) asInteger]. > y_off = new_y_off ifFalse: [ y_off: new_y_off. changed ]). > } | ) > > > > '-- Side effects' > > globals modules scroll postFileIn > >

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deadProxyError?
by Cameron Elliott 07 Nov '95

07 Nov '95

I am trying to write an HTTP server under Self, and am having a couple of problems. First, the Self VM is receiving a SIGPIPE when my application tries to write to a pipe that the other end has closed, and this causes a stack dump, searching through the system it looks like the Self world doesn't have to much of an interface to the unix signals mechanism, so it looks like I'm going to have to issue a signal(SIGPIPE,DFL_IGN); or whatever the call is to ignore a signal, and then exec the Snapshot with my http server. (This is fine) The problems I having are: I keep getting deadProxyError, and I don't what this is. After playing with my application a while I keep losing the ability to connect to a well defined port. (Somehow something is running somewhere in the Self VM which is still holding onto the port.) And when I 'start' my application again, I get a 'EADDRINUSE' error, even though as far as I can tell, the unixFile is (dead). I don't have a clue what the solution to the deadProxyError is, and it seems the key to fixing the EADDRINUSE problem is to find out what is holding onto my well known port address, and release it. And hints, clues, or experience is invited. Thanks Cameron Elliott

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Re: Hello, world!
by J.MALONEY＠AppleLink.Apple.COM 06 Nov '95

06 Nov '95

Hi, Michael, A don't think a scrollMorph should be very difficult to implement. The idea is to use the ability to set the clipping rectangle of a canvas, along with the ability of a canvas to translate all drawing operations by some offset. The scrolling morph would override the drawOn: method and would make a copy of the canvas with the desired offset and clipping box. It would then do "resend.drawOn:" passing this canvas as the argument. This one method should be all you need to get the output side working. On the input side (if you want things within the scrollMorph to be mouse-sensitive) you have to override the event dispatching method (whose name escapes me at the moment) to translate the coordinates in the incoming events in the appropriate way. Again, I think you only need to fix one method. By the way, I'm not saying it is obvious how to build a scrollMorph. I always meant to build one as an example, but there was always something a little bit higher on the priority list... Let us know if you build a scollMorph (and maybe even send us your code!). -- John

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Re: Use of X colors
by J.MALONEY＠AppleLink.Apple.COM 03 Nov '95

03 Nov '95

Lars, Self doesn't used shared colors because it recycles color map entries as necessary. Self doesn't used a fixed palette of colors; you can pick colors from the entire range of available colors. You can also use transient colors (in an animation, for example). In short, the user's model of color is that the entire 24-bit color space is always available. The system multiplexes the 256 color-map entries to maintain this illusion as best it can. On the other hand, color-map flashing is annoying. Self tries to avoid this by allocating only as many color-map entries as it needs from the globabl color map. As long as the total number of colors in use by Self and all other applications is under 256, Self will share the global color map and no flashing will occur when moving the cursor between windows. However, if Self need more colors than are available in the global colormap, it creates its own private one, resulting in color-map switching when moving between applications. Unfortuntately, the implementation does not handle multiple Self windows on the same screen as well as it should; every Self window gets its own set of colors instead of sharing them with the other Self windows on that screen. Multiple Self windows are likely to quickly exhaust the color map and force some of the windows to start using their own private color maps. By the way, what kind of X server are you using? -- John

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Re: Use of X colors
by J.MALONEY＠AppleLink.Apple.COM 03 Nov '95

03 Nov '95

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Re: Use of X colors
by J.MALONEY＠AppleLink.Apple.COM 03 Nov '95

03 Nov '95

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Use of X colors
by Lars R{der Clausen 02 Nov '95

02 Nov '95

I wonder why Self allocates a private colormap for each window instead of requesting shared colors as long as possible? That would eliminate the color flashing when you have several windows open. Or maybe there is a good reason for this? -Lars -- Lars Clausen Amiga, BSD, Linux, DOS & ZX in one box elascurn(a)daimi.aau.dk USENET: over 6000 examples of chaos theory -P. Salus in '1/4 Century of UNIX'

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Re: Hello, world!
by Michael.Huebner＠PrakInf.TU-Ilmenau.DE 02 Nov '95

02 Nov '95

> I'll probably also make a proportional slider. There is already a sliderMorph in the Self world. What is missing is a scrollMorph, one that wraps another morph and shows only a part according to the position of the slider in the associated sliderMorph. I tried to do it but found that the assumption that no part of a morph should be hidden is 'built into' the design of the morph family. That's why you have to change a lot of general functionality (inherited from morph) to achieve a real scroller. This was to much work for me at this time. If you like I can send you the module with my first try. Michael

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Re: undo (was: wish list)
by dib＠signal.dra.hmg.gb 02 Nov '95

02 Nov '95

( I have thought a little more about this subject - a system that would ) only let you back up the whole world to some point in the past (it ( might even make this past read-only) would be enough for what I want ) as long as you could use the transporter (or something like it) to ( bring a clone of selected objects into the present! This wouldn't ) help your simulator at all, of course, since you aren't interested ( in a mostly linear time but in a "branching" time. Since the simulation is partitioned into objects, what usually happens is that each object has a linear time, though of course the overall emergent effect is branching as you say. Either way, making the past read-only does make life a *lot* easier. ( Anyway, for my application the past must be stored in a highly ) compressed form. Having the last N versions of objects hanging ( around would increase memory requirements - hardly what Self needs ) to be more popular :-) The memory overhead can be a real nuisance. (Even when you've got sufficient memory we've found that caches tend to perform less effectively, and that can be quite significant.) There has been some work on reversible systems that don't depend on storing additional versions but on reversible computations; this might then be of some interest. One recent example is Henry Baker's "NREVERSAL of Fortune --- The Thermodynamics of Garbage Collection" in the 1992 International Workshop on Memory Management. David Bruce ---- post: DRA Malvern, St Andrews Road, Malvern, Worcestershire WR14 3PS, ENGLAND email: (internet) dib(a)dra.hmg.gb or dib%hermes.mod.uk(a)relay.mod.uk phone: +44 1684 895112 ** fax: +44 1684 894389 or 894540 ** telex: 339747

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Self-interest November 1995