Variables

Values with names. The first three blocks are this script's own variables: pick one from the drop-down, or choose Rename variable to name it. A name that starts with $ makes it a global variable instead. The global variable blocks below them read and write the values every script and robot skill in ARCx shares.

Where to find it: the Variables category of the toolbox, in any script editor set to Blockly or on Top bar → Workspaces → Blockly

Blocks

Details

Get Variable

Reads the current value stored inside a variable and makes it available to connect to other blocks. Variables are like labelled boxes that store information.

When to use it: Use this whenever you need to use a value that was stored earlier — like using a saved sensor reading, or displaying a score.

Example: Get variable "speed" → gives you the current speed value so you can use it in a Move block.

Tips:

• Click the dropdown to choose which variable to get.
• You can use the same variable in many places throughout your script.
• If the variable hasn't been set yet, it will be undefined — always set it first.

In JavaScript: this block gives back the value of

.yyAXoJkn;v)tiTn+y_/

Set Variable

Saves a value into a named variable so you can use it later. Whatever was in the variable before is replaced with the new value.

When to use it: Use this to remember important values — like saving a sensor reading, keeping score, or storing the result of a calculation.

Example: Set "distance" to Get Ping → reads the sensor and saves the distance in a variable for later use.

Tips:

• Create new variables by clicking the dropdown and selecting "New variable..."
• Variable names should describe what they hold — like "speed" or "playerScore".
• A variable holds just one value at a time — setting it again replaces the old value.

In JavaScript: this block runs

.yyAXoJkn;v)tiTn+y_/ = 0;

Clear Variable

Resets a variable by clearing its value, setting it back to undefined (empty/nothing). This is different from setting it to 0 or "" — it truly has no value.

When to use it: Use this when you want to "reset" a variable to its starting state, or signal that it hasn't been assigned a real value yet.

Example: Clear "lastDetectedColor" → the variable is now empty, and you can check for null to know it hasn't been set.

Tips:

• After clearing, comparing the variable to null returns true.
• Use this at the start of a loop to reset values from the previous run.
• Clearing is not the same as setting to 0 — null means "no value", not "zero".

In JavaScript: this block runs

delete .yyAXoJkn;v)tiTn+y_/;

Set global variable … to …

Store a value in a global variable with setVar(). Every script and robot skill in the project can read it, and it shows in the Variable Watcher.

In JavaScript: this block runs

setVar('myVariable', 0);

Global variable …

The value of a global variable, with getVar(). The script stops with an error if the variable does not exist - use the "or if missing" block when it might not.

In JavaScript: this block gives back the value of

getVar('myVariable')

Global variable … or … if missing

The value of a global variable, or the value given here when the variable does not exist.

In JavaScript: this block gives back the value of

getVar('myVariable', 0)

Global variable … exists

True when a global variable with this name has been set, with varExists().

In JavaScript: this block gives back the value of

varExists('myVariable')

Delete global variable …

Remove a global variable, with deleteVar(). Reading it afterwards is an error until it is set again.

In JavaScript: this block runs

deleteVar('myVariable');

Set global variable … to … description …

Store a value in a global variable with setVar(), and describe what it is for. The description shows in the Variable Watcher. Leave it empty to keep the one the variable already has.

In JavaScript: this block runs

setVar('myVariable', 0, 'What this variable is for');

Set global variable … to a copy of …

Store a snapshot of a list or object in a global variable with setVarObject(). Unlike set, changing the original afterwards does not change what was stored.

In JavaScript: this block runs

setVarObject('myVariable', 0);