noGPS converter V1.0

-- noGPS converter
-- Version 1.0
-- by ChaosNicro

local arg = {...}

-- help
function help()
print("usage:")
print("converter <filename> <direction> <keep> ")
print("")
print("filename: Name of the file to convert.")
print("")
print("direction: Whether to convert the file to noGPS format(true)")
print("or revert a converted file back to the native format.")
print("")
print("keep: Whether to keep the original file (true) or to overwrite it (false).")
print("")
print("When keep is true the output will be named filename-noGPS.")
error() -- using empty prints instead of /n is a personal preference
end


-- variables
if (arg[1] == nil) or (not fs.exists(arg[1])) then
help()
end
local filename = arg[1] -- name of the original file
local direction -- true = convert, false = revert
if arg[2] == "false" then  direction = false elseif arg[2] == "true" then direction = true else help() end
local keep -- Whether to keep the original file
if arg[3] == "false" then  keep = false elseif arg[3] == "true" then keep = true else help() end
local currline = "something"
local convFilename = filename.."-converted"

-- handles
local orfile = assert(fs.open(filename, "r"), "could not open file")
local newfile = assert(fs.open(convFilename, "w"), "could not create new file")

-- logic
if direction then
newfile.writeLine("os.loadAPI(\"noGPS\")")
end
while true do
currline = orfile.readLine()
if (currline ~= nil) and (direction) then
currline = string.gsub(currline, "turtle.forward", "noGPS.forward")
currline = string.gsub(currline, "turtle.back", "noGPS.back")
currline = string.gsub(currline, "turtle.up", "noGPS.up")
currline = string.gsub(currline, "turtle.down", "noGPS.down")
currline = string.gsub(currline, "turtle.turnLeft", "noGPS.turnLeft")
currline = string.gsub(currline, "turtle.turnRight", "noGPS.turnRight")
newfile.writeLine(currline)
elseif (currline ~= nil) and (not direction) then
if currline ~= "os.loadAPI(\"noGPS\")" then
currline = string.gsub(currline, "noGPS.forward", "turtle.forward")
currline = string.gsub(currline, "noGPS.back", "turtle.back")
currline = string.gsub(currline, "noGPS.up", "turtle.up")
currline = string.gsub(currline, "noGPS.down", "turtle.down")
currline = string.gsub(currline, "noGPS.turnLeft", "turtle.turnLeft")
currline = string.gsub(currline, "noGPS.turnRight", "turtle.turnRight")
newfile.writeLine(currline)
end

elseif currline == nil then
break
end
end

orfile.close()
newfile.close()
if not keep then
fs.delete(filename)
fs.move(convFilename, filename)
end
print("finished!")