July 2015 - Pharo-dev - lists.pharo.org

Re: [Pharo-dev] Seeking help on morphs : expander and scrolls

by Nicolai Hess

what about "newTextEditorFor:" *dialog newRow: {* *(* * (* * dialog newExpander: r title asString* * forAll: { dialog newTextEditorFor: yourTextModel getText:#getTextSelector setText:#setTextSelector. }* * )minWidth:600; minHeight: 10* *)cellInset: 0;* * borderStyle: (BorderStyle inset baseColor: dialog paneColor; width: 1)* 2015-07-17 11:59 GMT+02:00 Jigyasa Grover <grover.jigyasa1(a)gmail.com>: > Hi > > I am using Expander Morphs to display some search results. > I am finding it hard to insert a scroll bar in text displayed after > expanding the title of the search result. > > The corresponding code snippet is as: > *dialog newRow: {* > *(* > * (* > * dialog newExpander: r title asString* > * forAll: { dialog newText: r content asString . }* > * )minWidth:600; minHeight: 10* > *)cellInset: 0;* > * borderStyle: (BorderStyle inset baseColor: dialog paneColor; width: 1)* > * } * > > I basically need to add a scroll-able content in '*newText*:' portion. > > The entire code of my application an offline text search application > namely searchQuick is available at github ( > https://github.com/jig08/sQuick_new) . > You all are welcome to fork the code , try the infancy application and > send in suggestions. > > Help Appreciated. > Regards > Jigyasa >

July 17, 2015

Seeking help on morphs : expander and scrolls

by Jigyasa Grover

Hi I am using Expander Morphs to display some search results. I am finding it hard to insert a scroll bar in text displayed after expanding the title of the search result. The corresponding code snippet is as: *dialog newRow: {* *(* * (* * dialog newExpander: r title asString* * forAll: { dialog newText: r content asString . }* * )minWidth:600; minHeight: 10* *)cellInset: 0;* * borderStyle: (BorderStyle inset baseColor: dialog paneColor; width: 1)* * } * I basically need to add a scroll-able content in '*newText*:' portion. The entire code of my application an offline text search application namely searchQuick is available at github (https://github.com/jig08/sQuick_new) . You all are welcome to fork the code , try the infancy application and send in suggestions. Help Appreciated. Regards Jigyasa

July 17, 2015

Re: [Pharo-dev] Comments in STON

by Sven Van Caekenberghe

> On 17 Jul 2015, at 09:00, stepharo <stepharo(a)free.fr> wrote: > > Hi sven > > > Le 16/7/15 21:28, Sven Van Caekenberghe a Ã©crit : >> Guille, >> >> I understand the problem. >> >> The reason is that STONCStyleCommentsSkipStream was/is a quick hack and does not know/understand anything about strings. >> >> It seems that the C preprocessor ignores comments in C strings, so we could consider adding that. > What is the C preprocessor. STONCStyleCommentsSkipStream was modelled (in concept) after the C preprocessor, cpp, https://en.wikipedia.org/wiki/C_preprocessor >> >> Basically STONCStyleCommentsSkipStream>>#nextNonCommentChar should know when it is inside a string and then ignore comments. But that means, in the case of STON/JSON, handling both ' (single) and " (double) quoted strings as well as interpret \' and \". All this should be doable, but it is not that easy to do elegantly. I'll see what I can do. >> >> Sven >> >>> On 16 Jul 2015, at 17:35, Guillermo Polito <guillermopolito(a)gmail.com> wrote: >>> >>> Hi Sven! >>> >>> I'm finally using the new STON with comments and I found one little problem: my ston file has urls :/ >>> >>> { >>> // comment ok, skipped >>> /* comment ok, skipped */ >>> "aURL": "http://ouch.it.will.be.skipped/and/break?my=ston" >>> } >>> >>> That is, doing: >>> >>> STON fromStreamWithComments: '{ >>> // comment ok, skipped >>> /* comment ok, skipped */ >>> "aURL": "http://ouch.it.will.be.skipped/and/break?my=ston" >>> }' readStream >>> >>> Will fail with an invalid input error because after skipping comments my STON stream remains like >>> >>> STON fromStreamWithComments: '{ >>> "aURL": "http: >>> } >>> >>> Any thoughts? >>> Guille >>> >>> El dom., 14 de jun. de 2015 a la(s) 3:06 a. m., stepharo <stepharo(a)free.fr> escribiÃ³: >>> >>> >>> Le 10/6/15 20:39, Sven Van Caekenberghe a Ã©crit : >>>>> On 10 Jun 2015, at 15:13, stepharo <stepharo(a)free.fr> wrote: >>>>> >>>>> This is in the entreprise book. I added a subsection on comments. >>>>> May be I committed but forgot to push. >>>>> Now I did it. >>>> And now I see it. >>>> I made a small change. >>> super! >>> >>>>> Stef >>>>> >>>>> >>>>> Le 9/6/15 21:50, Sven Van Caekenberghe a Ã©crit : >>>>>> Where exactly can I find what you changed ? >>>>>> I don't see any commit of you on github ... >>>>>> >>>>>>> On 09 Jun 2015, at 20:10, stepharo <stepharo(a)free.fr> wrote: >>>>>>> >>>>>>> >>>>>>> >>>>>>> Le 9/6/15 20:06, stepharo a Ã©crit : >>>>>>>> I will update the STON chapter :) >>>>>>> Done :) >>>>>>> >>>>>>>> Le 8/6/15 23:39, Sven Van Caekenberghe a Ã©crit : >>>>>>>>> I would do it like this: use a wrapping stream to skip comments. >>>>>>>>> >>>>>>>>> === >>>>>>>>> Name: STON-Core-SvenVanCaekenberghe.59 >>>>>>>>> Author: SvenVanCaekenberghe >>>>>>>>> Time: 8 June 2015, 11:34:32.886167 pm >>>>>>>>> UUID: 7ab942b5-9d1a-44c3-9d58-da29feb72380 >>>>>>>>> Ancestors: STON-Core-SvenVanCaekenberghe.58 >>>>>>>>> >>>>>>>>> Add experimental STONCStyleCommentsSkipStream and tests >>>>>>>>> === >>>>>>>>> Name: STON-Tests-SvenVanCaekenberghe.54 >>>>>>>>> Author: SvenVanCaekenberghe >>>>>>>>> Time: 8 June 2015, 11:34:52.918771 pm >>>>>>>>> UUID: 3dcb2c9c-6efe-4d62-bf36-3bbe91f09d08 >>>>>>>>> Ancestors: STON-Tests-SvenVanCaekenberghe.53 >>>>>>>>> >>>>>>>>> Add experimental STONCStyleCommentsSkipStream and tests >>>>>>>>> === >>>>>>>>> >>>>>>>>> Then you can do as follows: >>>>>>>>> >>>>>>>>> STON fromStream: (STONCStyleCommentsSkipStream on: 'Point[/* this is X*/ 1, /* this is Y*/ 2] // Nice huh ?' readStream). >>>>>>>>> >>>>>>>>> => 1@2 >>>>>>>>> >>>>>>>>> STON fromStream: (STONCStyleCommentsSkipStream on: '// Here is how you create a point: >>>>>>>>> Point[ >>>>>>>>> // this is X >>>>>>>>> 1, >>>>>>>>> // this is Y >>>>>>>>> 2 ] >>>>>>>>> // Nice huh ?' readStream). >>>>>>>>> >>>>>>>>> => 1@2 >>>>>>>>> >>>>>>>>> This helper class would be useable in other contexts too (like NeoJSON). >>>>>>>>> >>>>>>>>> The advantage is that it does not change the STON (or JSON) syntax itself, it just add some functionality for those who want it. >>>>>>>>> >>>>>>>>> What do you think ? >>>>>>>>> >>>>>>>>> Sven >>>>>>>>> >>>>>>>>> PS: this probably needs some more testing >>>>>>>>> >>>>>>>>>> On 08 Jun 2015, at 17:16, Sven Van Caekenberghe <sven(a)stfx.eu> wrote: >>>>>>>>>> >>>>>>>>>>> On 08 Jun 2015, at 17:03, Damien Cassou <damien.cassou(a)inria.fr> wrote: >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> Sven Van Caekenberghe <sven(a)stfx.eu> writes: >>>>>>>>>>> >>>>>>>>>>>> I am not so sure we should add that. >>>>>>>>>>>> >>>>>>>>>>>> The JSON spec explicitly does not allow comments because of fear of abuse (that the comments would be used to add semantic meaning outside the spec). >>>>>>>>>>> really? That's surprising. Comments in configuration files are very >>>>>>>>>>> important. Even more when the configuration files are templates for new >>>>>>>>>>> users. >>>>>>>>>> I know some people are using STON in ways that I did not originally anticipate, that is of course cool, but writing configuration files was not the original goal. STON is a version of JSON that is closer to our object model. >>>>>>>>>> >>>>>>>>>> Like I said, I will think about it. >>>>>>>>>> >>>>>>>>>>> -- >>>>>>>>>>> Damien Cassou >>>>>>>>>>> http://damiencassou.seasidehosting.st >>>>>>>>>>> >>>>>>>>>>> "Success is the ability to go from one failure to another without >>>>>>>>>>> losing enthusiasm." --Winston Churchill >>>> >>> >> >> > >

July 17, 2015

Re: [Pharo-dev] [Pharo-users] Searching for similiar projects

by Jigyasa Grover

Yes Stephan Though I am still not able to resolve the error. -- View this message in context: http://forum.world.st/Searching-for-similiar-projects-tp4837427p4837917.html Sent from the Pharo Smalltalk Developers mailing list archive at Nabble.com.

July 17, 2015

Re: [Pharo-dev] Comments in STON

by stepharo

Hi sven Le 16/7/15 21:28, Sven Van Caekenberghe a Ã©crit : > Guille, > > I understand the problem. > > The reason is that STONCStyleCommentsSkipStream was/is a quick hack and does not know/understand anything about strings. > > It seems that the C preprocessor ignores comments in C strings, so we could consider adding that. What is the C preprocessor. > > Basically STONCStyleCommentsSkipStream>>#nextNonCommentChar should know when it is inside a string and then ignore comments. But that means, in the case of STON/JSON, handling both ' (single) and " (double) quoted strings as well as interpret \' and \". All this should be doable, but it is not that easy to do elegantly. I'll see what I can do. > > Sven > >> On 16 Jul 2015, at 17:35, Guillermo Polito <guillermopolito(a)gmail.com> wrote: >> >> Hi Sven! >> >> I'm finally using the new STON with comments and I found one little problem: my ston file has urls :/ >> >> { >> // comment ok, skipped >> /* comment ok, skipped */ >> "aURL": "http://ouch.it.will.be.skipped/and/break?my=ston" >> } >> >> That is, doing: >> >> STON fromStreamWithComments: '{ >> // comment ok, skipped >> /* comment ok, skipped */ >> "aURL": "http://ouch.it.will.be.skipped/and/break?my=ston" >> }' readStream >> >> Will fail with an invalid input error because after skipping comments my STON stream remains like >> >> STON fromStreamWithComments: '{ >> "aURL": "http: >> } >> >> Any thoughts? >> Guille >> >> El dom., 14 de jun. de 2015 a la(s) 3:06 a. m., stepharo <stepharo(a)free.fr> escribiÃ³: >> >> >> Le 10/6/15 20:39, Sven Van Caekenberghe a Ã©crit : >>>> On 10 Jun 2015, at 15:13, stepharo <stepharo(a)free.fr> wrote: >>>> >>>> This is in the entreprise book. I added a subsection on comments. >>>> May be I committed but forgot to push. >>>> Now I did it. >>> And now I see it. >>> I made a small change. >> super! >> >>>> Stef >>>> >>>> >>>> Le 9/6/15 21:50, Sven Van Caekenberghe a Ã©crit : >>>>> Where exactly can I find what you changed ? >>>>> I don't see any commit of you on github ... >>>>> >>>>>> On 09 Jun 2015, at 20:10, stepharo <stepharo(a)free.fr> wrote: >>>>>> >>>>>> >>>>>> >>>>>> Le 9/6/15 20:06, stepharo a Ã©crit : >>>>>>> I will update the STON chapter :) >>>>>> Done :) >>>>>> >>>>>>> Le 8/6/15 23:39, Sven Van Caekenberghe a Ã©crit : >>>>>>>> I would do it like this: use a wrapping stream to skip comments. >>>>>>>> >>>>>>>> === >>>>>>>> Name: STON-Core-SvenVanCaekenberghe.59 >>>>>>>> Author: SvenVanCaekenberghe >>>>>>>> Time: 8 June 2015, 11:34:32.886167 pm >>>>>>>> UUID: 7ab942b5-9d1a-44c3-9d58-da29feb72380 >>>>>>>> Ancestors: STON-Core-SvenVanCaekenberghe.58 >>>>>>>> >>>>>>>> Add experimental STONCStyleCommentsSkipStream and tests >>>>>>>> === >>>>>>>> Name: STON-Tests-SvenVanCaekenberghe.54 >>>>>>>> Author: SvenVanCaekenberghe >>>>>>>> Time: 8 June 2015, 11:34:52.918771 pm >>>>>>>> UUID: 3dcb2c9c-6efe-4d62-bf36-3bbe91f09d08 >>>>>>>> Ancestors: STON-Tests-SvenVanCaekenberghe.53 >>>>>>>> >>>>>>>> Add experimental STONCStyleCommentsSkipStream and tests >>>>>>>> === >>>>>>>> >>>>>>>> Then you can do as follows: >>>>>>>> >>>>>>>> STON fromStream: (STONCStyleCommentsSkipStream on: 'Point[/* this is X*/ 1, /* this is Y*/ 2] // Nice huh ?' readStream). >>>>>>>> >>>>>>>> => 1@2 >>>>>>>> >>>>>>>> STON fromStream: (STONCStyleCommentsSkipStream on: '// Here is how you create a point: >>>>>>>> Point[ >>>>>>>> // this is X >>>>>>>> 1, >>>>>>>> // this is Y >>>>>>>> 2 ] >>>>>>>> // Nice huh ?' readStream). >>>>>>>> >>>>>>>> => 1@2 >>>>>>>> >>>>>>>> This helper class would be useable in other contexts too (like NeoJSON). >>>>>>>> >>>>>>>> The advantage is that it does not change the STON (or JSON) syntax itself, it just add some functionality for those who want it. >>>>>>>> >>>>>>>> What do you think ? >>>>>>>> >>>>>>>> Sven >>>>>>>> >>>>>>>> PS: this probably needs some more testing >>>>>>>> >>>>>>>>> On 08 Jun 2015, at 17:16, Sven Van Caekenberghe <sven(a)stfx.eu> wrote: >>>>>>>>> >>>>>>>>>> On 08 Jun 2015, at 17:03, Damien Cassou <damien.cassou(a)inria.fr> wrote: >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> Sven Van Caekenberghe <sven(a)stfx.eu> writes: >>>>>>>>>> >>>>>>>>>>> I am not so sure we should add that. >>>>>>>>>>> >>>>>>>>>>> The JSON spec explicitly does not allow comments because of fear of abuse (that the comments would be used to add semantic meaning outside the spec). >>>>>>>>>> really? That's surprising. Comments in configuration files are very >>>>>>>>>> important. Even more when the configuration files are templates for new >>>>>>>>>> users. >>>>>>>>> I know some people are using STON in ways that I did not originally anticipate, that is of course cool, but writing configuration files was not the original goal. STON is a version of JSON that is closer to our object model. >>>>>>>>> >>>>>>>>> Like I said, I will think about it. >>>>>>>>> >>>>>>>>>> -- >>>>>>>>>> Damien Cassou >>>>>>>>>> http://damiencassou.seasidehosting.st >>>>>>>>>> >>>>>>>>>> "Success is the ability to go from one failure to another without >>>>>>>>>> losing enthusiasm." --Winston Churchill >>> >> > >

July 17, 2015

Re: [Pharo-dev] libSDL2 not present in full download

by jannik laval

Thank you Esteban ! Jannik 2015-07-17 8:38 GMT+02:00 Esteban Lorenzano <estebanlm(a)gmail.com>: > yesâ¦ no idea why, they should be in the distributionâ¦ I will include them > when I come back from holidays. > > Esteban > > On 17 Jul 2015, at 08:27, jannik laval <jannik.laval(a)gmail.com> wrote: > > The problem is not about OSWindow, the problem is that the lib is not > included in the full download. > To reproduce: download "pharo all included" from > https://ci.inria.fr/pharo/ and you will see that the plugin is not there. > > Jannik > > 2015-07-16 21:10 GMT+02:00 Matthieu Lacaton <matthieu.lacaton(a)gmail.com>: > >> >> I have problems with saving the image while SDL2 windows are opened. >>> >> >> What OS are you using ? I don't seem to have this issue right now but >> I've already experienced it before. Do you have a way to reproduce it ? >> >> 2015-07-16 19:12 GMT+02:00 ClÃ©ment Bera <bera.clement(a)gmail.com>: >> >>> Hello, >>> >>> I am using SDL2 for a project and this project is in development. You >>> have to use the latest VM from files.pharo.org and load the bleeding >>> edge of OSWindow from its configuration in the latest Pharo 5. >>> >>> From my experience, it is usable but there are still a few issues like >>> the fullscreen mode is not working correctly for me and I have problems >>> with saving the image while SDL2 windows are opened. >>> >>> Best, >>> >>> Clement >>> >>> 2015-07-16 14:32 GMT+02:00 jannik laval <jannik.laval(a)gmail.com>: >>> >>>> Hi pharoers, >>>> >>>> I was trying to use OSWindow, but in a "full Download" (Image+VM), the >>>> plugin SDL2 is not present. >>>> Does this mean that the full download is based on an old VM ? >>>> It is the case for Pharo 4 and Pharo 5. >>>> >>>> Cheers, >>>> >>>> -- >>>> >>>> ~~Jannik Laval~~ >>>> Ãcole des Mines de Douai >>>> Enseignant-chercheur >>>> http://www.jannik-laval.eu >>>> http://www.phratch.com >>>> http://www.approchealpes.info >>>> http://car.mines-douai.fr/ >>>> >>> >>> >> > > > -- > > ~~Jannik Laval~~ > Ãcole des Mines de Douai > Enseignant-chercheur > http://www.jannik-laval.eu > http://www.phratch.com > http://www.approchealpes.info > http://car.mines-douai.fr/ > > > -- ~~Jannik Laval~~ Ãcole des Mines de Douai Enseignant-chercheur http://www.jannik-laval.eu http://www.phratch.com http://www.approchealpes.info http://car.mines-douai.fr/

July 17, 2015

Re: [Pharo-dev] libSDL2 not present in full download

by Esteban Lorenzano

yesâ¦ no idea why, they should be in the distributionâ¦ I will include them when I come back from holidays. Esteban > On 17 Jul 2015, at 08:27, jannik laval <jannik.laval(a)gmail.com> wrote: > > The problem is not about OSWindow, the problem is that the lib is not included in the full download. > To reproduce: download "pharo all included" from https://ci.inria.fr/pharo/ <https://ci.inria.fr/pharo/> and you will see that the plugin is not there. > > Jannik > > 2015-07-16 21:10 GMT+02:00 Matthieu Lacaton <matthieu.lacaton(a)gmail.com <mailto:matthieu.lacaton@gmail.com>>: > > I have problems with saving the image while SDL2 windows are opened. > > What OS are you using ? I don't seem to have this issue right now but I've already experienced it before. Do you have a way to reproduce it ? > > 2015-07-16 19:12 GMT+02:00 ClÃ©ment Bera <bera.clement(a)gmail.com <mailto:bera.clement@gmail.com>>: > Hello, > > I am using SDL2 for a project and this project is in development. You have to use the latest VM from files.pharo.org <http://files.pharo.org/> and load the bleeding edge of OSWindow from its configuration in the latest Pharo 5. > > From my experience, it is usable but there are still a few issues like the fullscreen mode is not working correctly for me and I have problems with saving the image while SDL2 windows are opened. > > Best, > > Clement > > 2015-07-16 14:32 GMT+02:00 jannik laval <jannik.laval(a)gmail.com <mailto:jannik.laval@gmail.com>>: > Hi pharoers, > > I was trying to use OSWindow, but in a "full Download" (Image+VM), the plugin SDL2 is not present. > Does this mean that the full download is based on an old VM ? > It is the case for Pharo 4 and Pharo 5. > > Cheers, > > -- > ~~Jannik Laval~~ > Ãcole des Mines de Douai > Enseignant-chercheur > http://www.jannik-laval.eu <http://www.jannik-laval.eu/> > http://www.phratch.com <http://www.phratch.com/> > http://www.approchealpes.info <http://www.approchealpes.info/> > http://car.mines-douai.fr/ <http://car.mines-douai.fr/> > > > > > -- > ~~Jannik Laval~~ > Ãcole des Mines de Douai > Enseignant-chercheur > http://www.jannik-laval.eu <http://www.jannik-laval.eu/> > http://www.phratch.com <http://www.phratch.com/> > http://www.approchealpes.info <http://www.approchealpes.info/> > http://car.mines-douai.fr/ <http://car.mines-douai.fr/>

July 17, 2015

Re: [Pharo-dev] libSDL2 not present in full download

by jannik laval

The problem is not about OSWindow, the problem is that the lib is not included in the full download. To reproduce: download "pharo all included" from https://ci.inria.fr/pharo/ and you will see that the plugin is not there. Jannik 2015-07-16 21:10 GMT+02:00 Matthieu Lacaton <matthieu.lacaton(a)gmail.com>: > > I have problems with saving the image while SDL2 windows are opened. >> > > What OS are you using ? I don't seem to have this issue right now but I've > already experienced it before. Do you have a way to reproduce it ? > > 2015-07-16 19:12 GMT+02:00 ClÃ©ment Bera <bera.clement(a)gmail.com>: > >> Hello, >> >> I am using SDL2 for a project and this project is in development. You >> have to use the latest VM from files.pharo.org and load the bleeding >> edge of OSWindow from its configuration in the latest Pharo 5. >> >> From my experience, it is usable but there are still a few issues like >> the fullscreen mode is not working correctly for me and I have problems >> with saving the image while SDL2 windows are opened. >> >> Best, >> >> Clement >> >> 2015-07-16 14:32 GMT+02:00 jannik laval <jannik.laval(a)gmail.com>: >> >>> Hi pharoers, >>> >>> I was trying to use OSWindow, but in a "full Download" (Image+VM), the >>> plugin SDL2 is not present. >>> Does this mean that the full download is based on an old VM ? >>> It is the case for Pharo 4 and Pharo 5. >>> >>> Cheers, >>> >>> -- >>> >>> ~~Jannik Laval~~ >>> Ãcole des Mines de Douai >>> Enseignant-chercheur >>> http://www.jannik-laval.eu >>> http://www.phratch.com >>> http://www.approchealpes.info >>> http://car.mines-douai.fr/ >>> >> >> > -- ~~Jannik Laval~~ Ãcole des Mines de Douai Enseignant-chercheur http://www.jannik-laval.eu http://www.phratch.com http://www.approchealpes.info http://car.mines-douai.fr/

July 17, 2015

Re: [Pharo-dev] [Vm-dev] Copy-on-write for a multithreaded VM

by Eliot Miranda

Hi Ben, On Thu, Jul 16, 2015 at 8:29 PM, Ben Coman <btc(a)openinworld.com> wrote: > > I am curious what are the issues holding us back from a multithreaded > VM being mainstream, since I had a passing thought about a strategy > for a partial-multi-threaded-VM. > The issue is the image. The class library, the tools, etc are essentially single-threaded. Making the VM multi-threaded is only a relatively small part of the job. Rewriting the rest of the system to be thread-safe is a big job. Hence my focus on simply providing a threaded VM that supports sharing the Vm between threads so that any and all external calls are non-blocking. This is a really useful first stage. Maybe later economic activity around Pharo and/or Squeak will motivate and support work on a multi-threaded system, but that's on a further horizon than having the kind of interconnectivity a smaller first step provides. Further, Smalltalk's strong encapsulation is so good at providing a distributed programing framework which uses lots of interconnected images that that's also an attractive route to go that yields value with far less effort than a fully multi-threaded system, and of course is more generally useful. > > I see multi-threading been prototyped before with RoarVM [1] & HydraVM > [2], and the CogBlog project page [3] says "While multi-threading > seems like an obvious and important direction to take the system in, > making the VM multi-threaded per-se **does not provide any benefit > before the Smalltalk image is made thread-safe** and that is > probably more work than providing a multi-threaded VM. Hence a > potentially more profitable approach is to concentrate on federating > multiple VMs running multiple images, communicating through the > threaded FFI." > > So I agree it would be a big job to make the whole Image thread-safe, > but I wonder if a useful subset would be threads that are unable to > disturb the system state? This might cover a lot of needs for > parallelism, for example: > * Complex force layouts with Roassal > * Web server worker threads > * Screen rendering by #fullDraw: & #drawOn: > > A copy-on-write facility might provide this, such that any required > system state changes require manual coding in the parent-thread to > process a result object returned from the child-thread when it exits. > This might be implemented by combining Spur's new features for: > * immutability > * lazy become forwarding > > Implementation might require an extra object header bit WriteCopied > and a new class CopyOnWriteThread known by the VM. > > Whenever a child-COWT reads an object, if WriteCopied is not set, set > both it and the Immutable bits. Any thread writing to that object > will trigger the existing immutability handler, which now > additionally, when WriteCopied is set: > 1. Creates a new WriteCopiedIndirection object holding > a. the old object > b. the newly written object > c. the thread that performed the write. > 2. Sets the old object's forward-pointer to that. > > Later the forward-following code observes the LocalCopy bit and based > on matching the current thread with that stored in 1c. unrolls the > correct object. The child-COWT leaves the WriteCopied bit set so as > to avoid immutability being set again. Actually that precludes using > real-immutability in a COWT, so my description above is not ideal - > but hopefully is enough to show intent. > Build it, they will come! > > Could this avoid needing to make the whole image thread safe? and thus > facilitate running Smalltalk worker threads across multiple CPUs? > > > Actually, this might even be useful without running across multiple > CPUs, since the cause of several intermittent Red-Screen-Of-Deaths was > due to using multiple green-threads to improve UI interactivity. (For > example forking update of Monticello lists to allow typing into search > boxes. Here #drawOn: had "aList size" returning different values > halfway through the algorithm. Where execution forked to provide this > useful feature was the best place for code readability and intuitive > understanding, but it was long path to trace through execution to > discover the coupling between there and the rendering code. Certainly > the fix is less readable that the original.) > > [1] https://github.com/smarr/RoarVM > [2] http://squeakvm.org/~sig/hydravm/devnotes.html > [3] http://www.mirandabanda.org/cogblog/cog-projects/ > > cheers -ben > -- _,,,^..^,,,_ best, Eliot

July 17, 2015

Copy-on-write for a multithreaded VM

by Ben Coman

I am curious what are the issues holding us back from a multithreaded VM being mainstream, since I had a passing thought about a strategy for a partial-multi-threaded-VM. I see multi-threading been prototyped before with RoarVM [1] & HydraVM [2], and the CogBlog project page [3] says "While multi-threading seems like an obvious and important direction to take the system in, making the VM multi-threaded per-se **does not provide any benefit before the Smalltalk image is made thread-safe** and that is probably more work than providing a multi-threaded VM. Hence a potentially more profitable approach is to concentrate on federating multiple VMs running multiple images, communicating through the threaded FFI." So I agree it would be a big job to make the whole Image thread-safe, but I wonder if a useful subset would be threads that are unable to disturb the system state? This might cover a lot of needs for parallelism, for example: * Complex force layouts with Roassal * Web server worker threads * Screen rendering by #fullDraw: & #drawOn: A copy-on-write facility might provide this, such that any required system state changes require manual coding in the parent-thread to process a result object returned from the child-thread when it exits. This might be implemented by combining Spur's new features for: * immutability * lazy become forwarding Implementation might require an extra object header bit WriteCopied and a new class CopyOnWriteThread known by the VM. Whenever a child-COWT reads an object, if WriteCopied is not set, set both it and the Immutable bits. Any thread writing to that object will trigger the existing immutability handler, which now additionally, when WriteCopied is set: 1. Creates a new WriteCopiedIndirection object holding a. the old object b. the newly written object c. the thread that performed the write. 2. Sets the old object's forward-pointer to that. Later the forward-following code observes the LocalCopy bit and based on matching the current thread with that stored in 1c. unrolls the correct object. The child-COWT leaves the WriteCopied bit set so as to avoid immutability being set again. Actually that precludes using real-immutability in a COWT, so my description above is not ideal - but hopefully is enough to show intent. Could this avoid needing to make the whole image thread safe? and thus facilitate running Smalltalk worker threads across multiple CPUs? Actually, this might even be useful without running across multiple CPUs, since the cause of several intermittent Red-Screen-Of-Deaths was due to using multiple green-threads to improve UI interactivity. (For example forking update of Monticello lists to allow typing into search boxes. Here #drawOn: had "aList size" returning different values halfway through the algorithm. Where execution forked to provide this useful feature was the best place for code readability and intuitive understanding, but it was long path to trace through execution to discover the coupling between there and the rendering code. Certainly the fix is less readable that the original.) [1] https://github.com/smarr/RoarVM [2] http://squeakvm.org/~sig/hydravm/devnotes.html [3] http://www.mirandabanda.org/cogblog/cog-projects/ cheers -ben

July 17, 2015