# Execution

`import { Execution } from "destack:runtime";`

Execution selection for one world.

```ds title="Execution"
export enum Execution {
    Strict = 1,
    Fast = 2,
    Record = 3,
    Replay = 4,
}
```

[language/library/src/runtime/world.ds:35:44](https://github.com/destack-sh/destack/blob/main/language/library/src/runtime/world.ds#L35-L44)

## Variants

### `Strict = 1`

Strict execution through runtime-owned facts and effect boundaries.

### `Fast = 2`

Fast execution with minimal runtime mediation.

### `Record = 3`

Record execution for later replay.

### `Replay = 4`

Replay one previously recorded trace.