[Etoys] Etoys Based Activity - FreeCell Sugar interactions

Milan Zimmermann milan.zimmermann at sympatico.ca
Tue May 5 01:27:56 EDT 2009

On May 4, 2009, Bert Freudenberg wrote:
> On 04.05.2009, at 07:31, Milan Zimmermann wrote:
> > Hi Bert,
> >
> > I finally did some investigation into Squeak interaction with DBus and
> > Datastore. I went through the classes that implement the DBus and
> > Datastore
> > interaction. This is some great stuff! Among others, if I understand
> > this correctly, your Squeak DBus client framework could, for
> > example, allow to use Squeak to write a KDE or gnome panel applet?
> > But that is an aside.
> Yes indeed. 

Very cool. I think such functionality could also add interest in Squeak... 
Would  it makes sense to add Squeak to this list


> A fun way to explore it is to run Squeak on a regular KDE/
> Gnome desktop and open the DBus Explorer from the World menu. You can,
> for example, find the screen saver on the session bus and tell it to
> blank the screen ...

Or exiting any application :) This is worth a blog by itself. 
	World Menu -> Open ->  DbusExplorer. 
	Expand DBus sessionBus
	open KDE system konsole
	yellow(middle or right)-click, select "invoke method"
	konsole gone
> > As Step 1, my goal was to figure out how to save a project in
> > Journal from a set of commands in Workspace. Going to the debugger,
> > I found that if I open a project in Etoys, and in a workspace, and do
> >
> >        Project current storeOnServerWithNoInteractionThenQuit.
> >
> > the project is saved in Journal, and on restart, Etoys must have read
> > the Journal saved project because it shows any changes I have made in
> > the project. It seems that the core method called from
> > storeOnServerWithNoInteractionThenQuit that interacts with Datastore
> > is
> >
> >        SugarDatastoreDirectory>> #writeProject: self
> >                                        inFileNamed: fileName
> >                                        fromDirectory: localDirectory
> >
> > So I tried to do the the same (Project current
> > storeOnServerWithNoInteractionThenQuit.) from a workspace in the
> > FreeCell activity. When performed, it does write to the Journal, but
> > upon restart, I get an exception that appears a DBus object cannot
> > be found -
> > picture attached.
> No, this is a regular file-not-found prompt. It looks like an file
> from the Datastore could not be opened. You should press alt-. at this
> prompt and investigate what it's trying to do.

I will debug it.

> > Could the difference be it because Freecell, on startup, does not
> > setup some DBus interaction?
> No, that should not be the problem.


> > Well in any case, I am looking for some help trying to figure this
> > out. I was thinking about these steps I'd like to achieve:
> >
> > 1) Command in Workspace that saves the FreeCell project on Journal.
> > I seem to be able to do that, but on fairly high level ( Project
> > current storeOnServerWithNoInteractionThenQuit.). Eventually I'd
> > like to get it done with more but lower level commands.
> Well. IMHO we should *not* save the whole project to the Journal. This
> is not supposed to be an Etoys activity, but a Squeak application. It
> should only store and retrieve its relevant state. For starters I'd
> only store the statistics, which is about 10 numbers.

I did not think of saving only the state of the game, but it is definitely a  
better approach. Maybe I am missing something here though. For example, in 
Etoys, saving a project writes the whole project as a pr file - I assume .PR 
is some for of serialized everything in the project, not just what have 

When attempting to store only FreeCell's state, I have a few things to learn 
and understand: 
	- without looking I am surptised FreeCell's state is only 10 numbers, it 
seems that position of the cards must be more than that unless it's packed 
somehow - I will look
	- which objects represent the state stored 
	- how to serialize it (well that should be relatively straightforward knowing 
the objects)
	- what method will write the serialized FreeCell state to Journal
		instead of SugarDatastoreDirectory>>#writeProjectinFileNamed:fromDirectory:
	- what does assign the "ownership" of that file on Journal as FreeCell
	- how to deserialize the state
	- how to import it back to the game

> > 2) Sure and understood way to open the saved Journal Project in
> > FreeCell. (So far within Etoys it seems to work, but I have little
> > understanding of it. In FreeCell it does not)
> The regular Etoys Sugar startup happens in SugarLauncher>>startUp.


> There it looks for the ACTIVITY_ID parameter to see if we are actually
> running under Sugar, and an OBJECT_ID which is present if we are
> resuming a Journal entry.


> I think the best way would be to use different parameter names in
> the Etoys logic would not kick off

logic in SugarLauncher.startup?

>  and would not try to open the
> object as project, but we could provide our own startup method that we
> would simply call at the end of FreeCell.st.

and load the state read from the Datastore/Journal?
> > 3) A command or set of commands in workspace, which wil allow to
> > Rename the FreeCell project (and save on Journal under the new name)
> Renaming means nothing more than storing in the DataStore with
> different meta data. Inspect
> 	SugarDataStore new getProperties: someObjectId
> (see the SugarDataStore class example to find out object ids). This
> meta data is just a dictionary that you can modify and later pass to
> the datastore's "update" function.

ah i see - so the getProperties reads the database key-values and update just 
puts it back with whatever changes we may have done.

> You should try to create and retrieve a file for the datastore
> manually in a workspace first. Like in this example, where a file is
> first read from the datastore, then modified, the saved again:
> http://wiki.squeakland.org/display/sq/Saving+to+a+file+in+Sugar
> This is actually a pretty complete example of what would have to
> happen for FreeCell on startup and on saving (reading a datastore
> object on startup, and creating or updating the datastore object to
> save). The difference would be that no find call is necessary because
> we would know the object id (if any) already.

i saw the example but did not study it - actually I tried, but did not get far 
enough. I will play with it from workspace, and likely ask some  questions.

> One minor thing missing is that an activity is supposed to watch the
> journal entry so it catches e.g. renames done on the Journal screen.
> Etoys actually does this (try resuming an Etoys project, switch to
> Journal, rename it there, switch back to Etoys, name should have
> changed there, too). See #monitorJournalEntry.

I see - will play with that as well.

> > 4) Ability to start using the black Launcher ribbon on top, with the
> > standard Etoys project name a project stop widget that would call
> > the commands from 1 and 2. .
> Well if you look at the end of FreeCell.st you see the tool bar is
> explicitly toggled off. Before re-enabling it we would have to
> customize it (see class SugarNavigatorBar).

Ah I thought the bar was SugarLauncher. Another thing to look at.

> > 5) More interaction such as copy/paste on Journal
> What would you like to paste into FreeCell? Not sure how useful that
> would be.

Well I though of it as an exercise, rather then useful feature, but it could 
be used like this: User could copy and later paste another state of FreeCell 
from the Sugar black ribbon on the left - this would replace the current game 
with the one that was pasted

> > Do these goals and order make sense?
> >
> > I will try to maintain a blog about what I am playing with.
> >
> > http://mzimmerm.blogspot.com/2009/05/how-to-install-and-run-sugar-activit
> >y.html
> Nice. I commented about two misconceptions.

Thanks! That means that section of blog is really for a developer that wants 
to do things manually (rather then just install FreeCell by clicking 
"download" - I will modify the blog with that comment so it is less confusing
> > I am unfortunately frustratingly slow and sometimes fail to respond
> > for a long time, combination of lack of time and experience in this
> > area (Squeak/DBus/Sugar), but will keep going... Appreciate any help.
> Just take your time, I'm glad someone else is finally looking at this
> stuff :)

I am actually quite excited about this - you did lots of great stuff there 
that deserves attention, use, and maybe we can do some marketing for it :) by 
having a few blogs and a small tutorial at some point.  Long time ago I played 
with DCOP in KDE and Dbus is similar but that's not the point - The point is 
that apart from it's usefulness for Sugar, what you did can be also used for 
Squeak / Etoys applications to be integral part of KDE and Gnome desktops 
(perhaps even OS X - I am reading Dbus is ported there there but probably not 
integrated). I especially like the idea trying to write a  KDE Panel applet in 
Squeak :)

ok time to go, I have stuff to try during the week and weekend, but I should 
have some questions earlier...

Later, Milan

> - Bert -
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> Etoys at lists.laptop.org
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