SKS-BASIC

tArgs = {...}
	
--Extract from StrUtils by tomass1996 of computercraft.info
--Link: http://www.computercraft.info/forums2/index.php?/topic/42-cc13string-utils-api/
	function find(str, match, startIndex)  --Finds @match in @str optionally after @startIndex
			if not match then return nil end
			str = tostring(str)
			local _ = startIndex or 1
			local _s = nil
			local _e = nil
			local _len = match:len()
			while true do
					local _t = str:sub( _ , _len + _ - 1)
					if _t == match then
							_s = _
							_e = _ + _len - 1
							break
					end
					_ = _ + 1
					if _ > str:len() then break end
			end
			if _s == nil then return nil else return _s, _e end
	end
	function seperate(str, divider)  --Separates @str on @divider
			if not divider then return nil end
			str = tostring(str)
			local start = {}
			local endS = {}
			local n=1
			repeat
					if n==1 then
							start[n], endS[n] = find(str, divider)
					else
							start[n], endS[n] = find(str, divider, endS[n-1]+1)
			end
					n=n+1
			until start[n-1]==nil
			local subs = {}
			for n=1, #start+1 do
					if n==1 then
							subs[n] = str:sub(1, start[n]-1)
					elseif n==#start+1 then
							subs[n] = str:sub(endS[n-1]+1)
					else
							subs[n] = str:sub(endS[n-1]+1, start[n]-1)
			end
			end
			return subs
	end
	
	--Now, my stuff - this is the function that reads a file into a table
	function readFileLines(filename)
	 file = fs.open(filename,"r")
	 local tLines = {}
	 repeat
	  line = file.readLine()
	  table.insert(tLines,line)
	 until line == nil
	 file.close()
	 return tLines
	end
	
	--And this - this is the interpreter
	function runFile(runfilename)
	 local lines = readFileLines(runfilename)
	 local number = 1
	 repeat
	  line = seperate(lines[number]," ")
	  if line[1] == "PRINT" then
	   num = 2
	   repeat
		write(line[num].." ")
		num = num+1
	   until line[num] == nil
	   print " "
	  elseif line[1] == "DISPLAY" then loadstring("print("..line[2]..")")()
	  elseif line[1] == "GOTO" then setnum = tonumber(line[2]) number = setnum numchanged = true
	  elseif line[1] == "WAIT" then sleep(tonumber(line[2]))
	  elseif line[2] == "=" then loadstring(line[1].." = "..line[3])()
	  elseif line[1] == "INPUT" then loadstring(line[2].." = read()")()
	  elseif line[1] == "IF" and line[5] == "GOTO" then
	   local n = loadstring("if "..line[2].." "..line[3].." "..line[4].." then return "..tonumber(line[6]).." end")()
	  
		if n then
			number = n
			numchanged = true
		end
	  end
	  if numchanged ~= true then number = number+1
	  else numchanged = false
	  end
	 until lines[number] == nil
	end
runFile(tArgs[1])