Simple sleep

[OvercookedBeef]

Is there any way to make a simple sleep function?
eg.

print("A")
sleep(2)
print("B")

I actually started using my own (very simple, but enough for my usecase) language (which transpiles to Lua), since I think Lua may be too complex/annoying for some people, especially if they have do to the format below over and over: (among some other minor things)

print("A")
run_after(2, function()
    print("B")
end)

[A-Cloud-Ninja]

You can implement a sleep in the environment pretty easily by yielding the coroutine and passing a float/int as an argument, and parsing that in GDscript.

…

On Fri, Mar 28, 2025, 11:56 AM OvercookedBeef ***@***.***> wrote: Is there any way to make a simple sleep function? eg. print("A")sleep(2)print("B") I actually started using my own language (which transpiles to Lua), since I think Lua may be too complex/annoying for some people, especially if they have do to the format below over and over: print("A")run_after(2, function() print("B")end) — Reply to this email directly, view it on GitHub <#60>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABMKIGL5BVQ3G2CTQABQTQT2WVWJBAVCNFSM6AAAAABZ7367I2VHI2DSMVQWIX3LMV43ERDJONRXK43TNFXW4OZYGE2DCMRVG4> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[OvercookedBeef]

You can implement a sleep in the environment pretty easily by yielding the coroutine and passing a float/int as an argument, and parsing that in GDscript.

Thanks, I'm trying to understand this as I don't have any experience with coroutines in Lua. Are you saying I should have a sleep global, of the type LuaCoroutine, which I pass in from GDScript, and they then can do sleep.yield(1.5)? I'm looking at the Lua docs for coroutine and it looks like yield is typically done from inside the coroutine, so I don't think I'm understanding correctly

[A-Cloud-Ninja]

So, I can share some explicit sample code when I'm not typing from mobile, but if you built a function in Lua, `function sleep(t) ... end` and have it call coroutine.yield("SLEEP",t), you can manage the coroutine from GDscript, by getting the return from LuaCoroutine.resume(...).

…

On Fri, Mar 28, 2025, 12:19 PM OvercookedBeef ***@***.***> wrote: You can implement a sleep in the environment pretty easily by yielding the coroutine and passing a float/int as an argument, and parsing that in GDscript. Thanks, I'm trying to understand this as I don't have any experience with coroutine in Lua. Are you saying I should have a sleep global, of the type LuaCoroutine, which I pass in from GDScript, and they then can do sleep.yield(1.5)? I'm looking at the Lua docs for (coroutine)[ https://www.lua.org/pil/9.1.html] and it looks like yield is typically done from *inside* the coroutine, so I don't think I'm understanding correctly — Reply to this email directly, view it on GitHub <#60 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABMKIGITTJLTICBHVBRM6BT2WVZBRAVCNFSM6AAAAABZ7367I2VHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTENRVGUZDENQ> . You are receiving this because you commented.Message ID: ***@***.*** com>

[OvercookedBeef]

Thanks, some explicit code would be helpful

[OvercookedBeef]

@A-Cloud-Ninja Could you share some sample code please? Thanks

[Denneisk]

You can sleep using a timer created in Godot and coroutines, although being able to re-call the calling function from Godot is a bit hacky. Here's two examples, one as a Lua Node and the other from GDScript.

-- As a Lua Node
local node = {
	extends = Node
}

function node:_resume(co) -- Helper function to resume a coroutine
	coroutine.resume(co)
end


local function wait(self, time)
	local co = coroutine.running()
	if co then
		-- Calls this Node with the corresponding coroutine
		self:get_tree():create_timer(time).timeout:connect(Callable(self, "_resume"):bind(co))
		coroutine.yield() -- Yield the coroutine. The timer above will resume it
	else
		error("Tried to wait on non-coroutine.")
	end
end

node._ready = coroutine.wrap(function(self) -- Note this must be wrapped
	print("Hello from Lua Node at " .. Time:get_ticks_msec() / 1000.0)
	wait(self, 1)
	print("Hello again from Lua Node at " .. Time:get_ticks_msec() / 1000.0)
end)

return node

# In GDScript
var lua_state := LuaState.new()
lua_state.open_libraries(
	LuaState.Library.LUA_BASE |
	LuaState.Library.GODOT_UTILITY_FUNCTIONS | # For printing
	LuaState.Library.GODOT_ALL_LIBS | # For Time library
	LuaState.Library.LUA_COROUTINE) # Coroutines, necessary

var yieldable = lua_state.do_string("""
	local function wait(time)
		coroutine.yield("sleep", time)
		-- Passing "sleep" as a flag just so we can differentiate other
		-- yields if needed
	end

	-- Note I'm creating a coroutine here instead of wrapping.
	-- This is mostly personal preference
	return coroutine.create(function()
		print("Hello from Lua at " .. Time:get_ticks_msec() / 1000.0)
		wait(1) -- We don't need to pass self here because yielding is handled in GDScript
		print("Hello again from Lua at " .. Time:get_ticks_msec() / 1000.0)
	end)
""")

var callback := func(cb):
	var result = yieldable.resume()
	if result is Array and result[0] == "sleep":
		get_tree().create_timer(result[1]).timeout.connect(cb)

callback.call(callback.bind(callback)) # I don't know the elegant GDScript solution to this

You can probably put together a nicer interface, but the problem is really that the Lua->Godot interface can be a little clunky because of how differently the languages act.

Note that from the changes #80, it might be easier to handle with with awaiting, but I haven't tested that yet.

[gilzoide]

Hey folks! Sorry about the late response. Yeah, using the new and unreleased await from Lua is kind of the easiest way to do this.

So as already noticed by @Denneisk, I explain in #80 (comment) that I have been experimenting with the implementation of await for Lua. It's in the feature/await branch and you can test it by downloading lua-gdextension artifact from the latest build and extracting it in your project (make sure to open the GODOT_UTILITY_FUNCTIONS library in your LuaState).

Here's a quick test, seems to be working well for timers:

Note: await can only be called from coroutines, so I made all methods from LuaScripts run in coroutines just to have await available. I still have to pool them to avoid allocating one every time, which I have done before in Lua PluginScript, so I know well how to =]

[Denneisk]

I made all methods from LuaScripts run in coroutines just to have await available.

Neat!