Whats wrong with my function?

function fillSlot(slot) -- finish the stack
  until turtle.getItemSpace(slot) == 0 -- repeat until stack is complete
	turtle.select(slot) -- select slot
	turtle.suck() -- try to fill slot
	if turtle.getItemSpace(slot) == 0 then -- if slot was filled
	  turtle.suckDown() -- pick up all non matching items
	  for i = 1, 16 do --empty all items except for kept slots
		if i == 1 or i == 4 or i == 13 or i == 15 or i == 16 then -- kept slots
	   -- Do nothing
	 else
	   turtle.select(i) -- select non-kept slot
	   turtle.drop()	--place in chest
	 end
	  end
	else -- if slot was not filled
	  for i = 1, 16 do  --empty all items into "temporary holding area" except for kept slots
		if i == 1 or i == 4 or i == 13 or i == 15 or i == 16 then -- kept slots
	   -- Do nothing
	 else
	   turtle.select(i) -- select non-kept slots
	   turtle.dropDown() -- drop on floor (under turtle)
	 end
   end
	end
  end
end
fillSlot(1)

The error is Line 2 'end' expected to close function, but i believe I have all the ends

You start out line 2 with until but there is no repeat in front of it.

Repeat loops work like this..

repeat
--this code
until condition is met

--so this would continue until item space for slot 1 == 0
repeat
turtle.suck()
until turtle.getItemSpace(1) == 0

thank you, that worked.

Got another function that i cant find the issue with, though posting it here again would be better than starting a new thread:

function farmLine() -- farm 1 collum
    repeat
   loc:forward
    until turtle.detect() == true
repeat
   turtle.select(14)
   if turtle.compareDown() == true then
	 loc:right()
  loc:right()
  loc:forward()
  loc:left()
  loc:left()
  turtle.dig()
  turtle.select(1)
  turtle.place()
   else
	 loc:right()
  loc:right()
  loc:forward()
  loc:left()
  loc:left()
until loc.x == 0
repeat
   loc:left()
until loc.h == 2
end

the loc: comands are from Lyqud's location API and there isn't a problem with those.
Error is: line 7 function arguments expected.

Well, loc:forward up at the top needs parentheses. Most of the rest of it looks fine.

Wow, that's the second time I've done something silly like that. thank you for the help.