Advanced Lua Topics - Coroutines

local function myFirstCoroutine()
  print("Hi there, friend! I am a function running from a coroutine!")
end

local co = coroutine.create(myFirstCoroutine)

coroutine.resume(co)
print(coroutine.status(co))

local function runMe()
  print("Hey part 1 is going.")
  coroutine.yield()
  print("Oh hey again. Now I'm in part 2!")
end

local co = coroutine.create(runMe)

coroutine.resume(co) --#in this case, the function is not done yet so a call to coroutine.status(co) will return "suspended"
--#Prints "Hey part 1 is going"
print("We are back in the parent code!")
coroutine.resume(co) --#now status is "dead" because the function has reached the end of its code
--#Prints "Oh hey again. Now I'm in part 2!")

local function middleArguments()
  print("I'm at the beginning. Yielding now...")
  local arg1, arg2 = coroutine.yield("Hey, this string is passed back to the caller")
  print("Arg1: "..arg1)
  print("Arg2: "..arg2)
end

local co = coroutine.create(middleArguments)

local resume_success, str_arg = coroutine.resume(co) --#Status is true
--#I'm at the beginning. Yielding now...
print(str_arg) --#Prints "Hey, this string is passed back to the caller"
status = coroutine.resume(co, "Argument 1!", "Argument 2!") --#Status is false
--#Arg1: Argument 1!
--#Arg2: Argument 2!
end

local function eventPuller()
  print("Hi")
  local e = {os.pullEvent()}
  print(unpack(e))
end

local co = coroutine.create(eventPuller)
local resume_status = coroutine.resume(co) --#Contrary to what one might think, resume_status will always be true, even if a coroutine is dead

print(coroutine.status(co))

• Create the coroutine
• Resume it
• We are in the eventPuller function and print "Hi"
• We pull an event and print it, exiting the function
• We print the status, which you would think would be "dead"

• Create the coroutine
• Resume it
• We are in the eventPuller function and print "Hi"
• We print the status of the coroutine, which is actually "suspended"

local function eventPuller()
  print("In event puller")
  local arg = {coroutine.yield()}
  print(unpack(arg))
end

local function eventPuller()
  print("In event puller")
  local args = {coroutine.yield("char")} --#Let's request a char event
  print(args[2])
end

local co = coroutine.create(eventPuller)

local _, event_type = coroutine.resume(co)
local event = {os.pullEvent(event_type)}
coroutine.resume(co, unpack(event))

• Print "In event puller" and exit to the parent
• Pull a "char" event
• Go back to the coroutine and give it the events
• Print out the character that we pulled

local str = ""

local function saveString()
  while true do
	local e = {os.pullEvent("char")}
	str = str..e[2]
  end
end

local function writeString()
  while true do
	local e = {os.pullEvent("char")}
	write(e[2])
  end
end

local co1 = coroutine.create(saveString)
local co2 = coroutine.create(writeString)

local evt = {}
while true do
  coroutine.resume(co1, unpack(evt))
  coroutine.resume(co2, unpack(evt))

  evt = {os.pullEvent("char")}

  if evt[2] == " " then
	break --#If there's a space, jump out of the loop
  end

end
print("And the result of str is: "..str)

local function create( first, ... )
if first ~= nil then
  return coroutine.create(first), create( ... )
	end
	return nil
end
local function runUntilLimit( _routines, _limit )
	local count = #_routines
	local living = count
  
	local tFilters = {}
	local eventData = {}
	while true do
	 for n=1,count do
	  local r = _routines[n]
	  if r then
	   if tFilters[r] == nil or tFilters[r] == eventData[1] or eventData[1] == "terminate" then
		local ok, param = coroutine.resume( r, unpack(eventData) )
	 if not ok then
	  error( param )
	 else
	  tFilters[r] = param
	 end
	 if coroutine.status( r ) == "dead" then
	  _routines[n] = nil
	  living = living - 1
	  if living <= _limit then
	   return n
	  end
	 end
	end
	  end
	 end
  for n=1,count do
	  local r = _routines[n]
   if r and coroutine.status( r ) == "dead" then
	_routines[n] = nil
	living = living - 1
	if living <= _limit then
	 return n
	end
   end
  end
	 eventData = { os.pullEventRaw() }
	end
end
function waitForAny( ... )
	local routines = { create( ... ) }
	return runUntilLimit( routines, #routines - 1 )
end
function waitForAll( ... )
	local routines = { create( ... ) }
runUntilLimit( routines, 0 )
end

function waitForAny( ... )

 coroutines = { }
 add( ... )
 
 local running = true
 while running do
  for k, v in pairs( coroutines ) do
   coroutine.resume( v )
   if coroutine.status( v ) == "dead" then
    running = false
   end
  end
 end
end

function waitForAll( ... )

 coroutines = { }
 add( ... )

 local running = true
 while true do
  running = false
  for k, v in pairs( coroutines ) do
   coroutine.resume( v )
   if coroutine.status( v ) ~= "dead" then
    running = true
   end
  end
 end
end

function herp( )
 for i=1, 10 do
  print( "herp" )
  coroutine.yield()
 end
end

function derp( )
 while true do
  print( "derp" )
  coroutine.yield()
 end
end

waitForAny( herp, derp )
waitForAll( herp, derp ) --I'm not so rude as to not provide examples :D/>