coroutines.lua

-- co-routines in pico8 seem a bit "broken" ?
-- coresume only passes through the extra arguments once, which seems to fit the lua spec and I can live with that
-- but yield return values seem to be ignored? it only ever returns true/false and an error message if it failed?

-- the below code never displays any return values until the coroutine function stops yielding and hits the final return
left=0 right=1 up=2 down=3 fire1=4 fire2=5

function _init()
	counter = 0
	fn = cocreate(stuff)
	fn2 = cocreate(stuff2)
end

function _update60()
	if (btnp(fire1)) then
		counter+=1
		continue,result = coresume(fn,counter)
		continue2,result2 = coresume(fn2,counter)
	end
end

function _draw()
	cls()
	? counter,0,0
	? continue,0,10
	? result,0,20
	? continue2,0,30
	? result2,0,40
end

function stuff(a)
	-- this will yield forever because the parameters are only passed in once
	-- which makes sense because the actual function entry point only gets executed
	-- once, just wanted to confiem :)
	while(a<10) do
		yield("foo")
	end
	return "done"
end

function stuff2(thing)
	-- this returns nothing from coresume (other than the normal true/false)
	-- until the final return statement
	for i=0,10 do	
		yield("foo"..i)
	end
	return "done:"..thing
end