DialogueRunner

:file: src/dialogue_runner.dart
:symbol: DialogueRunner
:package: jenny

Execution model

The DialogueRunner uses futures as a main mechanism for controlling the timing of the dialogue progression. For each event, the dialogue runner will invoke the corresponding callback on all its DialogueViews, and each of those callbacks may return a future. The dialogue runner then awaits on all of these futures (in parallel), before proceeding to the next event.

For a simple .yarn script like this

title: main
---
Hello
-> Hi
-> Go away
   <<jump Away>>
===

title: Away
---
<<OhNo>>
===

the sequence of emitted events will be as follows (assuming the second option is selected):

• onDialogueStart()
• onNodeStart(Node("main"))
• onLineStart(Line("Hello"))
• onLineFinish(Line("Hello"))
• onChoiceStart(Choice(["Hi", "Go away"]))
• onChoiceFinish(Option("Go away"))
• onNodeFinish(Node("main"))
• onNodeStart(Node("Away"))
• onCommand(Command("OhNo"))
• onNodeFinish(Node("Away"))
• onDialogueFinish()

:::{note} Keep in mind that if a DialogueError is thrown while running the dialogue, then the dialogue will terminate immediately and none of the *Finish callbacks will run. :::