---
title: "performAction(in:)"
framework: gameplaykit
role: symbol
role_heading: Instance Method
path: "gameplaykit/gkrule/performaction(in:)"
---

# performAction(in:)

Performs actions that should result when the rule is satisfied in the context of the specified rule system.

## Declaration

```swift
func performAction(in system: GKRuleSystem)
```

## Discussion

Discussion A rule system calls this method when evaluating its rules, if and only if the rule’s predicate has been satisfied (that is, the evaluatePredicate(in:) method has returned true), and after moving the rule from its agenda list to its executed list. If the rule was created with the init(predicate:assertingFact:grade:) or init(predicate:retractingFact:grade:), calling this method asserts or retracts the fact as specified in the provided rule system. If the rule was created with the init(blockPredicate:action:) method, calling this method calls the action block. Otherwise, this method does nothing—subclasses should override this method to implement their own actions.

## See Also

### Evaluating a Rule

- [evaluatePredicate(in:)](gameplaykit/gkrule/evaluatepredicate(in:).md)