Yarn Return Jump Command

Example.yarn

title: Start
---
Hello, this is a trial for callback stack
-> Yes
  <<push SomeNode Start_1>>
-> No
Some spill over
===
title: Start_1
---
This is the continuation
It's kinda hacky but why not
Want to try it again?
-> Yes
  <<push SomeNode Start_2>>
-> No
  Okay then
  <<jump Start_2>>
===
title: Start_2
---
Want to do some multiple jump?
-> Yes
  <<push SomeJump Start_3>>
-> No
  <<jump Start_3>>
===
title: Start_3
---
This is the end
===

title: SomeNode
---
This is some node that asked something
Do you want to go back?
-> Yes
  <<pop>>
-> No
Some spill over
===

title: SomeJump
---
Jump Again?
-> Yes
  <<push SomeJumpAgain SomeJump_1>>
-> No
  <<jump SomeJump_1>>
===
title: SomeJump_1
---
End of Jump
<<pop>>
===

title: SomeJumpAgain
---
This is another jump.
Going back now.
<<pop>>
===

Explanation.markdown

This is a workaround about returning call. There are two new command:

• <<push toNode returnNode>>
• <<pop>>

Push Command

Basically it's the same as jump. It will jump to toNode, and push the returnNode to a stack.

Pop Command

It will pop the top of a stack and jump into that node.

Usage

Put YarnReturnjump.cs as a Component along side with DialogueRunner.

Caution

Please don't mix a <<jump>> and <<push>> with a same node. If that node expect something to be popped, it will behave strangely if you don't push something to the stack.

YarnReturnJump.cs

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using Yarn.Unity;

public class YarnReturnJump: MonoBehaviour
{
    private DialogueRunner dialogueRunner;

    private Stack<string> stack = new Stack<string>();
    public void Awake()
    {
        dialogueRunner = GetComponent<DialogueRunner>();
        if (!dialogueRunner) return;
        dialogueRunner.AddCommandHandler<string, string>("push", pushHandler);
        dialogueRunner.AddCommandHandler("pop", popHandler);
    }

    private void pushHandler(string node, string returnNode)
    {
        stack.Push(returnNode);
        StartCoroutine(JumpNextFrame(node));
    }

    private void popHandler()
    {
        StartCoroutine(JumpNextFrame(stack.Pop()));
    }
    private IEnumerator JumpNextFrame(string node)
    {
        // need to wait another frame, so this will execute after the command handler is finished
        yield return null;
        dialogueRunner.Stop();
        dialogueRunner.StartDialogue(node);
    }

}