variables retain value after opening and closing stack file

[xfrios]

In live code it looks like all variables etc retain their values when the application is restarted.

So, if I want to reinitialize all variables in the application (like I often want to after a debug/edit) I have to add code to do that.

Is that correct ?
Is there any other way ?

I am finding it a very strange experience with this data magically persisting even with application run & stop.

I am sure there is a good reason for it. Can someone explain the philosophy behind it? I guess I will not need to do a lot of specific writing to external files if all my application data magically persists.

Is this really the case when the application is deployed to platforms like iOS, or is this behavior only present in the development environment ?

[Klaus]

Hi xfrios,

you mean all your local and global and other variables are still there (with their last set value)
when you quit LiveCode and restart it again?

Hmmm, I have been using LiveCode (and its ancestors) for 12 years now and I have never
heard nor experienced this!?

Are you sure there is no initializing routine (e.G. from values of custom properties) going on somewhere?


Best

Klaus

[jacque]

As Klaus said, variables do not retain their values between launches unless you have initializing scripts that put values into them. If you are seeing something different, tell us how you are setting up your variables. Do you declare them specifically? Are they global, script local, or handler-specific? They aren't defined constants, are they?

I just noticed you say they are in a stack file. If you are closing the stack without quitting the app, and the stack's destroystack property is false, then the stack does not really close. It remains open in the background, but not in the message path, and no variable values will be removed. To really close the stack, set its destroystack property to true, or else have a script issue the command "delete this stack" -- which removes the stack completely from RAM. Note that if your variables are global, they won't be removed until your app quits, though you can manually remove them using the "delete global" command.

[xfrios]

Oops. The largest part of this problem was some of my own runtime initialization getting away from me in a big way. Sorry to bother you with that.

Your comments about stack destruction are useful, thanks!

[xfrios]

Ok, now I have my initialization under control, I can see the remainder.

When I close my stack and exit LiveCode, then re-open LiveCode and load my stack, all the fields are still populated with whatever data they had when the stack was closed. To be more specific:

1. Put "testing" into field fFormText
2. Manually close stack and exit LiveCode
3. Open LiveCode and Open stack
- the field fFormText still contains the data "testing"

I'm sure it's by design, but can you explain a bit about that?

It is probably something very obvious, but I am used to environments where this kind of data does not persist unless I explicitly save and load it. Is this an IDE feature only, or is saving this kind of form/field data just something that the LiveCode Runtime does on all target platforms?

I apologize for my ignorance, but I'm just not getting it.

Thanks!

[dglass]

I'm sure it's by design, but can you explain a bit about that?

It is probably something very obvious, but I am used to environments where this kind of data does not persist unless I explicitly save and load it. Is this an IDE feature only, or is saving this kind of form/field data just something that the LiveCode Runtime does on all target platforms?

I apologize for my ignorance, but I'm just not getting it.

Thanks!

I think it is because of the rather fuzzy relationship between editing mode and browse/run mode.

IMO, it is silly, and the IDE should take care of resetting these items when switching between the two modes. Others (including the runrev folks, it would seem) hold the opinion that this sort of 'resetting/initialization' is the responsibility of the programmer.

[BvG]

stuff is saved, if you save the stack. standalones cannot save itself, so within a standalone you need to save stacks into some other place to benefit from this feature.

[jacque]

Ok, now I have my initialization under control, I can see the remainder.

When I close my stack and exit LiveCode, then re-open LiveCode and load my stack, all the fields are still populated with whatever data they had when the stack was closed. To be more specific:

1. Put "testing" into field fFormText
2. Manually close stack and exit LiveCode
3. Open LiveCode and Open stack
- the field fFormText still contains the data "testing"

I'm sure it's by design, but can you explain a bit about that?

LiveCode will prompt you to save when you close the stack. If you agree, then the field content is saved. Try this:

1. Manually save the stack while the field content is empty.
2. Put "testing" into the field.
3. Close the stack. When LiveCode asks if you want to save, say no.
4. Quit LiveCode. Relaunch it and reopen the stack.

The field should be empty.

If the stack's destroystack property is true, then you don't even need to quit LiveCode. Just closing the stack (and not saving it) will remove it from RAM and when you reopen it, the field should not have any content.