Timer v2

loaded = false
dir = ""
file = ""
path = ""
internal = {}
local tArgs = {...}
local function create()
        local file = fs.open(path,"a")
        file.close()
end

local function load(directory,fileName)
        dir = directory
        file = fileName
        if dir ~= nil then
                path = dir.."/"..file
                fs.makeDir(dir)
                create(path)
                local file = fs.open(path, "r")
                repeat
                        line = file.readLine()
                        if(line ~= nil) then
                                local asWords = line:gsub(":","")
                                local parts = {}
                                for word in asWords:gmatch("%w+") do table.insert(parts,word) end
                                internal[parts[1]] = parts[2]
                        end
                until line == nil
                loaded = true
                file.close()
        else
                path = file
                create(path)
                local file = fs.open(path, "r")
                repeat
                        line = file.readLine()
                        if(line ~= nil) then
                                local asWords = line:gsub(":","")
                                local parts = {}
                                for word in asWords:gmatch("%w+") do table.insert(parts,word) end
                                internal[parts[1]] = parts[2]
                        end
                until line == nil
                loaded = true
                file.close()
        end
end

local function writeVal(key,value)
        if(loaded == false) then
                return false
        else
                local toWrite = value
                if(value == true) then toWrite = "true"
                elseif(value == false) then toWrite = "false" end
                internal[key] = toWrite
                return true
        end
end

local function readVal(key)
        if(loaded == false) then
                return nil
        end
        toReturn = internal[key]
        if(toReturn == "true") then return true
        elseif(toReturn == "false") then return false
        else return internal[key] end
end

local function save()
        if(loaded == true) then
                local file = fs.open(path,"w")
                for i,v in pairs(internal) do
                        file.writeLine(i.." = "..v)
                end
                file.close()
                internal = {}
                loaded = false
                return true
        else
                return false
        end
end

local function isEmpty()
        if(loaded == false) then
                return nil
        end
        if(fs.getSize(path) == 0)then
                return true
        else return false end
end

local function printUsage()
    print("Usage:")
    print(shell.getRunningProgram().." <interval> <side> <inputSide> (pulseTime)")
    print("Parameters:")
    print("[] = Required")
    print("() = Optional")
    return true
end

--Some basic error checking, will be a bit 'better' in future
if #tArgs < 3 and not fs.exists("config") then
    printUsage()
    return false
elseif #tArgs < 3 and fs.exists("config") then
    noArgsGood = true
end

if tArgs[1] == "usage" then
    printUsage()
    return false
end

if noArgsGood == nil then
    intVal = tonumber(tArgs[1])
    side = tArgs[2]
    iStop = tArgs[3]
    pTime = tonumber(tArgs[4])
    load(nil,"config")
    writeVal("intVal",tostring(intVal))
    writeVal("side",side)
    writeVal("iStop",iStop)
    writeVal("pTime",tostring(pTime))
    save()
elseif noArgsGood then
    load(nil,"config")
    intVal = tonumber(readVal("intVal"))
    side = readVal("side")
    iStop = readVal("iStop")
    pTime = tonumber(readVal("pTime"))
    save()
end

if pTime == nil then
    pTime = 0.2
end

while true do
    os.startTimer(intVal)
    local event = {os.pullEvent()}
    if event[1] == "redstone" and rs.getInput(iStop) then
        while true do
            local event = {os.pullEvent("redstone")}
            if event[1] == "redstone" and not rs.getInput(iStop) then
                break
            end
        end
    elseif event[1] == "timer" then
        rs.setOutput(side,true)
        sleep(pTime)
        rs.setOutput(side,false)
    end --TODO: Add the optional ability to stop with Rednet
end