declare persistent data for ?

[Fadden]

Hi,

I tried this code :

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declare persistent Integer[Text] RaidRecords;
RaidRecords["Paris-Dakar"] = 85542;

It works

But in most script I see "declare persistent data for something". For example in the TMPlatform script :

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declare persistent BestScore_NbRespawns for Map = -1;

What is the interest of "for ..." in this case ?

Thx

[steeffeen]

if you leave out the "for XY" it's equivalent to writing "for This"
This is always the context you're in, like CTmMode, CTmMlScriptIngame, CSmMode, etc.

that "for" part basically says that the Object is carrying the variable you are declaring
this way it will keep being accessible as long as the object is alive
the "persistent" modifier just says that the object should persist it so that it can still be accessed after a restart and a new object of the same type has been created

a

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declare persistent Variable for Map

has a different value than

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declare persistent Variable for User

because they are owned by different objects


similar to that there are the netwrite/netread modifiers

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declare netwrite Variable for UI

can be used to send data between server and client because the UI object synchronizes its owning variables between the two
->

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declare netread Variable for UI

for reading the Variable on the other end


it can be seen as "Key-Value-Coding" which is common in many languages

[Fadden]

Thanks you very much

[steeffeen]

that "for" part basically says that the Object is carrying the variable you are declaring
this way it will keep being accessible as long as the object is alive

just wanted to add a small note to make that more clear
if you declare the same variable again later on it will have the same value as earlier

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{
   declare Integer Var for This;
   Var = 5;
}
...
{
   declare Integer Var for This;
   log(Var);
}

prints "5"

[fleo]

And what about the following value? Is it used to initialised with this value or something? Let's take this example to keep with the persistent data ^^

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		declare persistent Boolean NadeoElite_PersistentShowRulesReminder for This = True;

If "= True" is to initialise, I don't get how the persistence is done...maybe only if this variable has no value yet.

[steeffeen]

maybe only if this variable has no value yet.

exactly
this statement defines the default value that is assigned if there is no value yet

[fleo]

Ok thanks a lot

[djhubertus]

Hey, If I want to use array as persistent (Integer[Integer]), how can I init the default value?

[maxi031]

Just declare it, it is initialized by default i think.
If you really want some default value go Array[0] = 1, or all values then loop for(i,0,maxNumber){Array = someValue} that is how i did it.
Or Array= [19, 85, 8, 24 ], or Array = [3 => 1, 2 => 11, 3 =>100, 7=12 ]
I think there is not fixed arrays just dynamic arrays. So you can grow them anytime you like.

[steeffeen]

an array is empty by default
so if you want to use an element that doesn't exist: set the default value, otherwise use it

you might be able to write something like

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declare A for Object = [1 => "First", 2 => "Second"];

but i wouldn't recommend doing so
especially as changing the default value later to add a new element would most likely lead to an error

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declare A for Object = [1 => "First", 2 => "Second", 3 => "Third"];
log(A[3]); // <- probably error because it's not initialized

instead:

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if (!A.existskey(1)) {
    A[1] = "First";
}
log(A[1]);

i know it's more code but it's safe