[Question] Is there a way to safely Wait/Delay execution in REPL and startup.cs?

[Lusiiky]

Hello,

For context, I am currently with a game built on Unity 6000, using a MelonLoader nightly build (IL2CPP), and the latest version of UnityExplorer.

My goal is to execute a command, wait for a few seconds (or wait for a scene to reload), and then execute another command. For example: calling a RestartGame() method, waiting for the new scene to load, and then modifying a newly spawned manager.

However, I've hit a wall trying to implement a delay inside the REPL / startup.cs evaluator:

1. System.Threading.Thread.Sleep(5000) freezes the Unity Main Thread entirely, so the game never actually loads the new scene during the wait.
2. Task.Delay().ContinueWith(...) throws a System.InvalidOperationException: The current SynchronizationContext may not be used as a TaskScheduler error in the REPL.
3. Trying to wrap the code inside a local function, a class, or an IEnumerator (to use WaitForSeconds or MelonCoroutines) results in Mono Evaluator syntax errors like error CS1525: Unexpected symbol or error CS0201. The evaluator seems to strictly process top-to-bottom flat statements.

My questions:

• Is there a built-in UnityExplorer method or a specific REPL syntax trick to achieve a non-blocking wait/yield inside startup.cs?
• If not, would it be possible to consider adding a built-in UE helper for this in the future? (e.g., something like UnityExplorer.Wait(5f, () => { /* code */ }); that handles the Coroutine safely behind the scenes).

Thank you for your time!

[yukieiji]

How about using pause to stop the entire game when you want to run the REPL?

[Lusiiky]

@yukieiji

How about using pause to stop the entire game when you want to run the REPL?

Because I would like to run an initial command, apply it with a restart, but wait a few seconds for the game to restart before running another command.
If the game is completely paused, nothing can happen.

[yukieiji]

When the game restarts, the MOD process will terminate, and I think the results of the executed commands won't be retained.
What exactly are you trying to do?

[Lusiiky]

@yukieiji

When the game restarts, the MOD process will terminate, and I think the results of the executed commands won't be retained. What exactly are you trying to do?

It's not a restart of the game in the sense that it closes and reopens, it's an internal METHOD within the game that restarts it.

What my script does is activate developer mode by modifying a property of an internal object within the game. Then I modify the BuildType to unlock some things in the game. Then I restart with a developer METHOD to apply the BuildType.
Except that after restarting, I would like to modify another value, which resets during the restart, even though it is in DontDestroyOnLoad, the value seems to be modified during the restart.

[yukieiji]

Please stop mentioning me..
First of all, what game are you using?
And do you have a detailed understanding of what that Restart method does? (Can you definitively state that overwriting that value is not part of the specification?)

[xi-lu]

Here are some notes that might help clarify how the C# Console works in UnityExplorer:

1. Built-in Coroutine Helpers

UnityExplorer already provides pre-defined shortcut methods in the C# Console:

• Start(IEnumerator) — starts a coroutine
• Stop(Coroutine) — stops a coroutine
  

  UnityExplorer/src/CSConsole/ScriptInteraction.cs

  Lines 26 to 30 in 2cfa85a

  	public static Coroutine Start(IEnumerator ienumerator)
  	=> RuntimeHelper.StartCoroutine(ienumerator);
  	public static void Stop(Coroutine coro)
  	=> RuntimeHelper.StopCoroutine(coro);

2. REPL vs. Class Definition — Different Evaluation Paths

The Mono.CSharp evaluator handles REPL statements and class definitions differently. For REPL input, the code is wrapped inside a method and compiled as a CompiledMethod. This means you cannot mix class-level constructs (class, using, etc.) with REPL expressions in the same input.

UnityExplorer/src/CSConsole/ConsoleController.cs

Lines 226 to 235 in 2cfa85a

	CompiledMethod? repl = _evaluator.Compile(input);
	if (repl != null)
	{
	REPLInvoke(repl);
	}
	else
	{
	CsCompile(supressLog);
	}

Note: It is possible to work around the using limitation by implementing a simple lexical analyzer to separate using directives from REPL code before passing them to the evaluator.

3. How to Achieve Delayed / Coroutine Execution

Option A: Manual invocation (works out of the box)

Define your coroutine inside a class:

using UnityEngine;
public class MyScript
{
    public static IEnumerator MyCoroutine()
    {
        Deubg.Log("Start");
        yield return new WaitForSeconds(2f);
        Debug.Log("Done after 2 seconds");
    }
}

Then call it manually in the console:

Start(MyScript.MyCoroutine());

Option B: Auto-invoke Main() (requires modifying UnityExplorer)

It is possible to patch UnityExplorer to automatically detect and call a Main() method from user-defined classes upon evaluation. I have tested this and confirmed it works. If there is interest, I can open a PR for this.