local/global "persistant" variables, in scripts/functions

[Shroom]

I just tried to add some variables into a script and then reference them in a function and I got an upvalue error - wtf is that :p

Code: Select all

local bool1 = false

function test()
  if not bool1 then

  end
end

Thats literally all i put and then on hitting preview I got the code error

[antti]

You need to either define the local variable inside the function or use a global variable.

[Shroom]

You need to either define the local variable inside the function or use a global variable.

oh so there is no such thing as local to that script entity - i see (I was thinking of each script as a class in c#)

Thanks for the heads up

[petri]

Well, to be precise, there are no "global" variables. E.g.

Script1:

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-- this variable is contained in the script entity, so it is "local" to the script
-- it will be saved/restored when loading a saved game
foo = 1  

function doSomething()
  -- local variable to function doSomething
  -- since the variable will be out of scope when doSomething() returns, it's value won't be saved
  local a = 0 
end

Script2:

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-- this variable is separate from 'foo' in script1
-- modifying this variable does not have effect on script1's foo
foo = 2


function blah()
  -- this will create a new variable in script2's scope
  -- it is NOT local to function blah() so it will be saved/restored from save games
  bar = "test"
end  

[Billick]

Well, to be precise, there are no "global" variables. E.g.

Script1:

Code: Select all

-- this variable is contained in the script entity, so it is "local" to the script
-- it will be saved/restored when loading a saved game
foo = 1  

function doSomething()
  -- local variable to function doSomething
  -- since the variable will be out of scope when doSomething() returns, it's value won't be saved
  local a = 0 
end

Script2:

Code: Select all

-- this variable is separate from 'foo' in script1
-- modifying this variable does not have effect on script1's foo
foo = 2


function blah()
  -- this will create a new variable in script2's scope
  -- it is NOT local to function blah() so it will be saved/restored from save games
  bar = "test"
end  

So... in other words variables are persistent, but not global.

[Shroom]

Thanks for clearing that up petri

To summarise

There are no global variables
To make a variable global to the script entity it is in (and persistant through saves) put it outside of the functions and simply declare it ie foo = 1
to make a variable local to a function (and therefore only exist as long as that function instance is being run), put it within the function declaration and use local in front of it

Can I access a variable from a different script ie script1.foo or is that limited to function calls?

Is there any diference then in declaring a variable inside or outside of a function if I do not use local?

[Lmaoboat]

Thanks for clearing that up petri

To summarise

There are no global variables
To make a variable global to the script entity it is in (and persistant through saves) put it outside of the functions and simply declare it ie foo = 1
to make a variable local to a function (and therefore only exist as long as that function instance is being run), put it within the function declaration and use local in front of it

Can I access a variable from a different script ie script1.foo or is that limited to function calls?

According to the patch notes, script1.foo should work.

[cromcrom]

So, does it mean I can create a "variable_storage" script entity (SE), define variable YYY in it (not in a function, just in the SE), and access/change it using variable_storage.YYY , and this new YYY variable will be saved through saved games ?
if yes, it's huge, and it's gonna make my numerous skills easier to use and create ^^

[antti]

So, does it mean I can create a "variable_storage" script entity (SE), define variable YYY in it (not in a function, just in the SE), and access/change it using variable_storage.YYY , and this new YYY variable will be saved through saved games ?
if yes, it's huge, and it's gonna make my numerous skills easier to use and create ^^

For the most part, yes. The only thing is that you can't change the variables like this from some other script entity though:

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variable_storage.exampleVariable = 1 		-- this doesn't work from outside the variable_storage entity

But instead you can do a setter function for it in the variable_storage like this for instance:

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function setVariable(variable, value)
	variable = value
end

And then refer to that function like this:

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variable_storage.setVariable(exampleVariable, 2)

Or you can alternatively build one setter function for each variable instead of a generic one like this if you want to introduce some variable specific functionality right in the setter (like checking if the value is within some specific bounds or error checking and so on).

[cromcrom]

Lol, that's great, it makes a neat trick. The bad side is that I am probably gonna have to redo many functions/items/SE. But it's really some good great news anyways ^^ Thanks a lot