stéphane ducasse a écrit :

This is a great question.

SmalltalkImage>>snapshot: save andQuit: quit embedded: embeddedFlag

the idea is that this is the same method that shutdown the image and that restart it. In fact when shutdoiwn the PC points on the next instruction to be executed that is to resume and restart the image :)

Stef

Ok so if I have understand what you say evry time I quit, the image while restart whith at the following instruction (base on my 3.8 image):

quit & (resuming == false) ifTrue: [self quitPrimitive].

"Here" -> Cursor normal show. Smalltalk setGCParameters. resuming == true ifTrue: [Smalltalk clearExternalObjects]. Smalltalk processStartUpList: resuming == true. resuming == true ifTrue:[ self setPlatformPreferences. self readDocumentFile]. Smalltalk isMorphic ifTrue: [SystemWindow wakeUpTopWindowUponStartup]. "Now it's time to raise an error" resuming == nil ifTrue: [self error:'Failed to write image file (disk full?)']. ^ resuming

___________________________________________________________________________ Yahoo! Mail réinvente le mail ! Découvrez le nouveau Yahoo! Mail et son interface révolutionnaire. http://fr.mail.yahoo.com

Greetings from Finland. I am very excited about Squeak and SmallTalk - I have find myself trying and exploring new programming things and that hasn't happen since days of Commodore 64.

Now I am trying to build (with one partner) a program which uses MySQL. I wonder what would be best way to do login screen and actual program.

Now we have morphs in windows which has login and password fields and button. At this time idea is that this startup screen test login information and then sends user (or user id) to another screen.

I tested various styles and this kind of test "works" with button.

test := DatabaseTest new. loginbutton := MyButtonMorph new send: #executeTest to: test"; openInHand".

But what would be the best way to send many variables or values with button click. (I have couple TextFieldMorphs storing values)

I have googled a lot - and most examples deals scriptable buttons. (And that is something I am not familiar with - as a novice I must see code and try different things and see what's happening...)

The problem with not testing my code:

Engine>>start "start the engine" [self fuel notEmpty] whileTrue: [ movement := self fuel burnFuelWith: self spark ]. self transmission addMovement: movement

Doesn't move until the gas runs out! :)

So how about:

Engine>>start "start the engine" self spark turnOnElectricity. self engageStarter. self car isKeyInOnPosition whileTrue: [ self runEngine ].

Engine>>runEngine "run engine and pass movement to car" self fuel notEmpty ifTrue: [ movement := self fuel burnFuelWith: self spark self transmission addMovement: movement ] ifFalse: [ self flashAnnoyingGasGuageLight. ].

Ok I realize I'm probably only amusing myself but just incase it helps someone I thought I'd point out my mistake!

Happy coding!

Ron

From: Ron Teitelbaum Sent: Tuesday, June 06, 2006 9:43 AM

Hi Marko,

How are things in Finland? I hear it is nice there and there seems to be a bit of a marketing campaign to get Americans to visit.

Anyway let's get to your question. There are a number of ways to pass variables around. The least effective way is to call methods with a lot of parameters. Usually when I see methods with lots of parameters there is a problem and the problem most likely is that the methods is implemented in the wrong class.

Consider for a moment an example (since you asked for code examples)

Object subclass: Car

Object subclass: Engine

Object subclass: Fuel

Object subclass: Spark

Now we all know that for engine it run it needs Fuel and Spark so we could model the car so that it has each

Car instanceVariables: 'engine fuel spark'

Then we have

Car>>start "Start the car" self engine startWithFuel: self fuel andSpark: self spark onCar: self

Engine>>startWithFuel: someFuel andSpark: someElectricity onCar: aCar "run the engine" [someFuel notEmpty] whileTrue: [ movement := someFuel burnFuelWith: someElectricity ]. aCar addMovement: movement

Car>>addMovement: someMovement "handle the movement of the engine through a transmission" self transmission handleMovement: someMovement

Ok so now I'm just amusing myself and thinking of the car being in idle so not using the fuel to move at all, wasting gas and promoting global warming.

Getting back to your question what would happen instead if we have the parameters modeled where they are needed. Ask yourself does the car need gas and fuel or does the engine need it instead?

So

Car instanceVariables: 'engine'

Engine instanceVariables: 'fuel spark transmission car'

Now when we build the objects we get much less parameter passing.

Car>>start "start the car" self engine start

Engine>>start "start the engine" [self fuel notEmpty] whileTrue: [ movement := self fuel burnFuelWith: self spark ]. self transmission addMovement: movement

Now this was a long answer to your question and you may be sitting there saying; "What does this have to do with databases and buttons"!

Well if you model your parameters in objects they don't need passing.

TestDatabase instanceVariables: 'dataSource user password myDBConnection'

Then your button's method #executeTest

TestDatabase>>executeTest self myDBConnection on: self dataSource logon: self user password: self password.

Where dataSource can have host and port and dbname ...

I hope this helps for specific examples you could try http://www.google.com/search?hl=en&q=mysql+squeak

If this doesn't make sense, feel free to ask questions. Let me know how it goes!

Happy coding!

Ron Teitelbaum President / Principal Software Engineer US Medical Record Specialists Ron@USMedRec.com

...

From: Marko Koivuniemi Sent: Monday, June 05, 2006 4:14 PM

Greetings from Finland. I am very excited about Squeak and SmallTalk - I have find myself trying and exploring new programming things and that hasn't happen since days of Commodore 64.

Now I am trying to build (with one partner) a program which uses MySQL. I wonder what would be best way to do login screen and actual program.

Now we have morphs in windows which has login and password fields and button. At this time idea is that this startup screen test login information and then sends user (or user id) to another screen.

I tested various styles and this kind of test "works" with button.

test := DatabaseTest new. loginbutton := MyButtonMorph new send: #executeTest to: test"; openInHand".

But what would be the best way to send many variables or values with button click. (I have couple TextFieldMorphs storing values)

I have googled a lot - and most examples deals scriptable buttons. (And that is something I am not familiar with - as a novice I must see code and try different things and see what's happening...)

-- Marko _______________________________________________ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners

---

Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners

Hello Mathieu,

HK> Another option is (not tested myself): HK> SmalltalkImage current snapshot: true andQuit:false. HK> self inform: yourStartupMessge.

forgot to tell you: this has to be done in a workspace with a _single_ doIt.

From Stef's reply I learned why this works. The instruction pointer will just continue where it left off in snapshot:andQuit.

Thanks Stef!

Cheers,

Herbert mailto:herbertkoenig@gmx.net