Variables

[Lobby]

Wouldn't it be useful to have some sort of state you can access from all of your plugins? That's what variables are for. They're stored globally for the whole city and can by accessed by any plugin. For now, variables can only hold integers. To access a variable you have to give it a name like $vars_switch_myvar. A great thing about variables is that they can be accessed from anywhere. Also, variables will be saved if the player leaves a city.

Set variable
Setting a variable is an action of type "set". The name of the variable is provided as "id". The value you want to assign can be provided with the "code"-tag which allows similar code as the "value" condition:

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"actions":[
  {"type":"set","id":"$vars_switch_myvar","code":"1-$vars_switch_myvar"}
]

This code updates the value of the variable $vars_switch_myvar to 1-$vars_switch_myvar. So calling this assignment multiple times would lead to a value sequence of 0,1,0,1,0,1,... (value of not assigned variables is 0).

Read variable
The sample code for setting a variable already uses code to read it, too (by using it in the "code"-tag). However, variables can also accessed by using a condition of type "value". In the "code" string you can provide a simple code that may contain variable names:

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"condition":{  // This condition is only true if $vars_switch_myvar==1
  "type":"value",
  "code":"$vars_switch_myvar",
  "z":1
}

Sample
I'll use variable $vars_switch_myvar to implement the following: I want to have a switch that can be switched by the user

switch.png

Then there should be indicators that show the current state of the switch

light.png

The code for it would then be

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[
  {
    "id":"$vars_switch00",
    "type":"decoration",
    "width":1,
    "height":1,
    "frames":[{"bmp":"switch.png","w":32,"h":16,"count":2}],
    "selectable frames":false,
    "random frame":false,
    "on click fun":[
      {
        "actions":[
          {"type":"set","id":"$vars_switch_myvar","code":"1-$vars_switch_myvar"},  // Switch state of variable between 0 and 1
          {"type":"frame","code":"$vars_switch_myvar"}  // Set frame accordingly
        ]
      }
    ],
    "fun":[
      {
        "actions":[{"type":"frame","code":"$vars_switch_myvar"}]  // Update frame on a daily basis (necessary if multiple switches exist)
      }
    ]
  },
  {
    "id":"$vars_light00",
    "type":"decoration",
    "width":1,
    "height":1,
    "frames":[{"bmp":"light.png","w":32,"h":16,"count":2}],
    "selectable frames":false,
    "random frame":false,
    "fun":[
      {
        "actions":[{"type":"frame","code":"$vars_switch_myvar"}]  // Update frame
      }
    ]
  }
]

Variable naming
Although you're pretty free in how you name your variables I recommend that it always starts with $ (variables without $ are supposed to be virtual). It also should contain name identifiers for you/your plugin to make name collisions with other plugins more unlikely.

[JustAnyone]

This should work in theory?

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"random fun": [{
"condition": {
      "type":"upgrade",
      "id":"dsahqupAR"
   },
   "actions": [{
    "type":"set",
    "id":"dsavar",
    "code":"1"
   }]
   }],
"requirements": [{
				"type":"CONDITION",
         "text":"Upgrade Required",
         "condition":{"type":"value","code":"dsavar","z":1}
			}],

[Bearbear76]

When can it start doing math?

[Lobby]

@JustAnyone doesn't it work?
@Bearbear65 actually, there's a bunch of integer operations supported within code. It's just bad documented...

[JustAnyone]

@JustAnyone doesn't it work?

Sorry! I've already fixed that. Forgot to mention it.

[Lobby]

So the math here is incrementing a counter? The example above contains something similar

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"actions":[
  {"type":"set","id":"$vars_switch_myvar","code":"1-$vars_switch_myvar"}
]

To just increment you could write

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"actions":[
  {"type":"set","id":"$other_var","code":"1+$other_var"} // $other_var := 1 + $other_var
]

[Lobby]

Supported operators are right now:

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a+b  // Sum of a and b
a-b  // Subtracts b from a
a*b  // Multiplies a by b
a/b  // Divides a by b
a%b  // Modulus operator on a and b (see https://en.wikipedia.org/wiki/Modular_arithmetic)
a^b  //Binary XOR operation on a and b (see https://en.wikipedia.org/wiki/Exclusive_or)

Special variables that are accessible in code:

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x  // Contains x value of the current context
y  // Contains y value of the current context

You can combine these operations, but you have to pay attention on their order as they'll always be executed from left to right (like simple calculators do). Here a condition that is only true for tiles that lie on a checkerboard like pattern

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{"type":"value","code":"x+y%2","z":0}  // (x+y)%2 can only be 0 or 1

[Lobby]

Try to replace . by _
I think valid variable names must not contain .

[KINGTUT10101]

Is it possible to have a variable which can only be read and changed by one building?

Like if I had a building like "theo.kt101" and I wanted to store the value "happiness" in each one, but each building placed will have their own "happiness" value that isn't global.

[Lobby]

The problem with fun is that it has quite simple functionality and adding special cases for each potential use case doesn't look like a real solution.

That's why I added support for Lua
The function to access the storage of a building is Tile.getBuildingStorage
If you need help with that please don't hesitate to send me a pm or make an own topic for it so that others can learn from it, too.

[KINGTUT10101]

Are we able to use less than and more than with variables? (< >)

[Lobby]

Yes, you can just write something like

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"condition":"x>0"

or even

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"condition":"y/2<=x+1"

Supported comparison operators are

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<=
>=
==
<
>

[yinx]

If I want to get the value of the variable daystofire and pass it into frames of type = date, how can I do that? I mean, I want the frames of the date to be set according to the daytofire variable

[Lobby]

iirc you cannot do this with fun

[yinx]

Thanks! I actually found a workaround by using merge to inject the JSON. The only downside is that the game won't update those variables on the fly—it requires a restart to take effect, which might be a bit annoying for players