Table of Contents

Variable Definition

A LunyScript.Script subclass provides the Var and GVar properties to access script variable storage.

Global vs Local Variables

Both global and local variables are the same type and share the same functionality.

  • GVar provides access to global variables.
  • Var contains local (object-bound / instance) variables.

The Var variables can have different values for the same variable name where a script runs on multiple objects.

Var variables can only be modified by its own script, thereby protecting them against accidental external changes. This is comparable to the protected / private access modifiers in C#.

Tip

Prefer to use Var. Use GVar only when you need to read/write same variable in multiple scripts/objects. This reduces the risk of accidentally defining identically named global variables for different uses.

Define A Variable Value

Before use, a variable should be defined. Optionally, an initial value can be set. Otherwise variables default to the value 0.

var zero = Var.Define("variable with default value 0");
var number = Var.Define("integer variable", 123);

Get Or Create A Variable

Index Var or GVar with a variable name to access the variable:

var theNumber = Var["integer variable"];
LunyLogger.LogInfo(theNumber.Value == Var["integer variable"].Value); // logs "true"

This will also work if the variable has not been defined. In this case the returned variable will have a default value of 0:

// will return a new variable with the value 0 
var newVar = Var["not defined"];
Tip

Prefer to use Define(). Be explicit about the variable definition, particularly the variable's type (number, boolean, string) matters. Arithmetic operations or comparisons may behave unexpectedly when the types mismatch: "hello" > 10 or true * 0.5. 🤔

Define A Constant Value

Constants disallow changes at runtime, the value can only be set once via the Constant() method:

var lightspeed = Var.Constant("speed of light in vacuum (m/s)", 299792458);

Other than being read-only, constants and variables function identically.

Note

Constant variables and modifiable variables are commonly subsumed under the term 'variable' in this documentation, even though "variable" suggests modifiability.

Setting Variable Value Immediately

To set a variable during build time, use SetImmediate():

var newVar = Var["does not exist yet"];
newVar.SetImmediate(959.697);
newVar.Set(137.248); // returns a runnable block, won't change value until block runs!

LunyLogger.LogInfo(Var["does not exist yet"]); // logs "959.697"!
Important

Arithmetic functions returning a ActionBlock instance like Set() will need to execute at runtime for the value to change. The SetImmediate() method executes during Build() time (immediately) and cannot be used like a block.

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