The Desktop Adventures engine includes a binary scripting language. Each zone can have a number of actions. Each action consists of conditions and instructions.

Conditions and instructions have the following structure:

type Condition = {
	opcode: number,
	arguments: number[5],
	text: string?

See Conditions and Instructions for a description of the known opcodes for conditions and instructions respectively.


Actions are evaluated on the current zone. Once every condition of an action is satisfied all instructions are executed. Consider this mock execution engine:

function execute(actions) {
	for (const action of actions) {
		if (action.conditions.every(condition => condition.isSatisfied()) {
			for (const instruction of action.instructions) {


There are several registers available for use in scripts. All registers are local to the zone.

  • counter – A simple 16-bit register
  • sector-counter16-bit register that is propagated to connected rooms
  • random16-bit register that can be set to random values