Basic mod data for the async tutorial

async-sct.lua

local mnProm = require("missionPromise")

engine.addHook("On Gameplay Start", function()
	async.run(function()
		mn.sendPlainMessage("Start of the coroutine!")

		local ship = async.await(mnProm.waitForShipAsync("TestShip"))

		mn.sendPlainMessage("Ship has arrived! Name: " .. ship.Name)
	end)
end)

async_test.fs2

#Mission Info

$Version: 0.10
$Name:  XSTR("Untitled", -1)
$Author: 
$Created: 05/21/20 at 23:11:05
$Modified: 05/29/20 at 16:37:24
$Notes:
This is a FRED2_OPEN created mission.
$End Notes:

$Mission Desc:
 XSTR("Put mission description here
", -1)
$end_multi_text
+Game Type Flags: 1
+Flags: 1024
+Fog Near Mult: 1.000000

+Fog Far Mult: 1.000000

+Disallow Support: 0
+Hull Repair Ceiling: 0.000000
+Subsystem Repair Ceiling: 100.000000

+Viewer pos: 0.000000, 150.000000, -200.000000
+Viewer orient:
	1.000000, 0.000000, -0.000000,
	0.000000, 0.866025, 0.500000,
	0.000000, -0.500000, 0.866025


$AI Profile: FS2 RETAIL

#Command Briefing

#Briefing
$start_briefing
$num_stages: 0
$end_briefing

#Debriefing_info

$Num stages: 0

#Players		;! 1 total

$Starting Shipname: Alpha 1
$Ship Choices: (
	"GTF Ulysses"	5
	"GTF Hercules"	5
	"GTF Hercules Mark II"	5
	"GTF Ares"	5
	"GTF Erinyes"	5
	"GTF Loki"	5
	"GTF Pegasus"	5
	"GTF Perseus"	5
	"GTF Myrmidon"	5
	"SF Mara (terrans)"	5
	"GTB Artemis"	5
	"GTB Artemis D.H."	5
	"GTB Medusa"	5
	"GTB Ursa"	5
	"GTB Zeus"	5
	"GTB Boanerges"	5
	"GVF Ptah"	5
)

+Weaponry Pool: (
	"Subach HL-7"	17
	"Subach HL-D"	16
	"Mekhu HL-7"	16
	"Mekhu HL-7D"	16
	"Akheton SDG"	16
	"Morning Star"	16
	"MorningStar D"	16
	"Prometheus R"	17
	"Prometheus S"	16
	"Prometheus D"	16
	"Maxim"	16
	"Maxim D"	16
	"UD-8 Kayser"	16
	"UD-D Kayser"	16
	"Circe"	16
	"Lamprey"	16
	"Rockeye"	500
	"Rockeye D"	500
	"Tempest"	500
	"Tempest D"	500
	"Hornet"	500
	"Hornet D"	500
	"Tornado"	500
	"Tornado D"	500
	"Harpoon"	516
	"Harpoon D"	500
	"Trebuchet"	500
	"TAG-A"	500
	"TAG-B"	500
	"Piranha"	500
	"Stiletto II"	500
	"Infyrno"	500
	"Infyrno D"	500
	"Cyclops"	500
	"Cyclops#short"	500
	"Helios"	500
	"EMP Adv."	500
)

#Objects		;! 3 total

$Name: Alpha 1		;! Object #0
$Class: GTF Ulysses
$Team: Friendly
$Location: 0.000000, 0.000000, 0.000000
$Orientation:
	1.000000, 0.000000, 0.000000,
	0.000000, 1.000000, 0.000000,
	0.000000, 0.000000, 1.000000
$AI Behavior: None
$Cargo 1:  XSTR("Nothing", -1)
+Initial Velocity: 33
+Initial Hull: 100
+Subsystem: Pilot
$Arrival Location: Hyperspace
$Arrival Cue: ( false ) 
$Departure Location: Hyperspace
$Departure Cue: ( false ) 
$Determination: 10
+Flags: ( "cargo-known" "player-start" )
+Flags2: ( )
+Respawn priority: 0
+Group: 0
+Use Table Score:
+Score: 8

$Name: TestShip		;! Object #1
$Class: GTF Ulysses
$Team: Friendly
$Location: -106.270683, 0.000000, 75.915436
$Orientation:
	1.000000, 0.000000, 0.000000,
	0.000000, 1.000000, 0.000000,
	0.000000, 0.000000, 1.000000
$AI Behavior: None
$Cargo 1:  XSTR("Nothing", -1)
+Initial Velocity: 33
+Initial Hull: 100
+Subsystem: Pilot
$Arrival Location: Hyperspace
$Arrival Cue: ( key-pressed "1" ) 
$Departure Location: Hyperspace
$Departure Cue: ( false ) 
$Determination: 10
+Flags: ( "cargo-known" )
+Flags2: ( )
+Respawn priority: 0
+Use Table Score:
+Score: 8

$Name: NotTestShip		;! Object #2
$Class: GTF Ulysses
$Team: Friendly
$Location: 93.849892, 0.000000, 77.233765
$Orientation:
	1.000000, 0.000000, 0.000000,
	0.000000, 1.000000, 0.000000,
	0.000000, 0.000000, 1.000000
$AI Behavior: None
$Cargo 1:  XSTR("Nothing", -1)
+Initial Velocity: 33
+Initial Hull: 100
+Subsystem: Pilot
$Arrival Location: Hyperspace
$Arrival Cue: ( key-pressed "2" ) 
$Departure Location: Hyperspace
$Departure Cue: ( false ) 
$Determination: 10
+Flags: ( "cargo-known" )
+Flags2: ( )
+Respawn priority: 0
+Use Table Score:
+Score: 8

#Wings		;! 1 total

$Name: Alpha
$Waves: 1
$Wave Threshold: 0
$Special Ship: 0		;! Alpha 1

$Arrival Location: Hyperspace
$Arrival Cue: ( true ) 
$Departure Location: Hyperspace
$Departure Cue: ( false ) 
$Ships: (		;! 1 total
	"Alpha 1"
)
+Hotkey: 0
+Flags: ( )

#Events		;! 0 total


#Goals		;! 0 total


#Waypoints		;! 0 lists total


#Messages		;! 0 total


#Reinforcements		;! 0 total


#Background bitmaps		;! 0 total

$Num stars: 500
$Ambient light level: 7895160
+Nebula: Nebula01
+Color: Blue
+Pitch: 116
+Bank: 310
+Heading: 148

#Asteroid Fields

#Music

$Event Music: None
$Briefing Music: None

#End

missionPromise.lua

local module = {}

function module.waitForShipAsync(ship_name)
	return async.promise(function(resolve, reject) end)
end

return module

missionPromiseExtended.lua

local module = {}

local arrivalChecks = {}

local hooksRegistered = false
function registerHooks()
	engine.addHook("On Warp In", function()
		local arrivedShip = hv.Self
		local callbacks = arrivalChecks[arrivedShip.Name]

		-- No one is interested in this ship :(
		if callbacks == nil then
			return
		end

		for _, v in ipairs(callbacks) do
			v.resolve(arrivedShip)
		end
		arrivalChecks[arrivedShip.Name] = nil
	end)

	engine.addHook("On Mission End", function()
		for _, checks in pairs(arrivalChecks) do
			for _, funcs in ipairs(checks) do
				funcs.reject("Mission has ended")
			end
		end
	end)

	hooksRegistered = true
end

function module.waitForShipAsync(ship_name)
	local existingShip = mn.Ships[ship_name]
	if existingShip:isValid() then
		-- Ship is already in mission, immediately resolve the promise
		return async.resolved(existingShip)
	end

	if not hooksRegistered then
		registerHooks()
	end

	-- Ship isn't here yet.
	-- TODO: Use the ship status caching from the engine to check if it may already have departed
	return async.promise(function(resolve, reject)
		local existingList = arrivalChecks[ship_name] or {}
		table.insert(existingList, { resolve=resolve, reject=reject })
		arrivalChecks[ship_name] = existingList
	end)
end

return module