Settings File API

--Settings File API used to parse and interpret and save settings files.
--Entirely created by bwhodle
--Forum post: http://www.computercraft.info/forums2/index.php?/topic/14311-preferences-settings-configuration-store-them-all-settings-file-api/
local function trimComments(line)
    local commentstart = string.len(line)
    for i = 1, string.len(line) do
        if string.byte(line, i) == string.byte(";") then
            commentstart = i - 1
            break
        end
    end
    return string.sub(line, 0, commentstart)
end
local function split(line)
    local equalssign = nil
    for i = 1, string.len(line) do
        if string.byte(line, i) == string.byte("=") or string.byte(line, i) == string.byte(":") then
            equalssign = i - 1
        end
    end
    if equalssign == nil then
        return nil, nil
    end
    return string.sub(line, 1, equalssign - 1), string.sub(line, equalssign + 2)
end
function Trim(s)
    return (s:gsub("^%s*(.-)%s*$", "%1"))
end
local function RemoveQuotes(s)
    if string.byte(s, 1) == string.byte("\"") and string.byte(s, string.len(s)) == string.byte("\"") then
        return string.sub(s, 2, -2)
    end
    return s
end
function openSettingsFile(path)
    local settings = {}
    local currentsection = {}
    local currentsectionname = nil
    local file = fs.open(path, "r")
    local lines = true
    settings["content"] = {}
    while lines do
        local currentline = file.readLine()
        if currentline == nil then
            lines = false
            break
        end
        currentline = trimComments(currentline)
        if Trim(currentline) ~= "" then
            if string.byte(currentline, 1) == string.byte("[") then
                if currentsectionname ~= nil then
                    settings["content"][currentsectionname] = currentsection
                    currentsection = {}
                elseif currentsectionname == nil then
                    settings["content"][1] = currentsection
                    currentsection = {}
                end
                currentsectionname = string.sub(currentline, 2, -2)
            else
                local key, value = split(currentline)
                if Trim(key) ~= nil and Trim(value) ~= nil then
                    local x = Trim(value)
                    if tonumber(x) then
                        x = tonumber(x)
                    else
                        x = RemoveQuotes(x)
                    end
                    if x ~= nil and tostring(Trim(key)) ~= nil then
                        currentsection[Trim(key)] = x
                    end

                end
            end
        end
    end
    if currentsectionname ~= nil then
        settings["content"][currentsectionname] = currentsection
        currentsection = {}
    elseif currentsectionname == nil then
        settings["content"][1] = currentsection
        currentsection = {}
    end

    function settings.addSection(name)
        settings["content"][name] = {}
    end

    function settings.getValue(key)
        local x = settings["content"][1]
        return x[key]
    end

    function settings.getSectionedValue(section, key)
        return settings["content"][section][key]
    end

    function settings.setValue(key, value)
        settings["content"][1][key] = value
    end

    function settings.setSectionedValue(section, key, value)
        settings["content"][section][key] = value
    end

    function settings.save(path)
        local file = fs.open(path, "w")
        local d = settings["content"][1]
        if d ~= nil then
            for k, v in pairs(d) do
                local x = v
                if string.byte(v, 1) == string.byte(" ") or string.byte(v, string.len(v)) == string.byte(" ") then
                    x = "\""..v.."\""
                end
                file.writeLine(k.." = "..x)
            end
        end
        for k, v in pairs(settings["content"]) do
            if k ~= 1 then
                file.writeLine("")
                file.writeLine("["..k.."]")
                for j, l in pairs(v) do
                    local x = l
                    if string.byte(l, 1) == string.byte(" ") or string.byte(l, string.len(l)) == string.byte(" ") then
                        x = "\""..l.."\""
                    end
                    file.writeLine(j.." = "..x)
                end
            end
        end
        file.close()
    end

    return settings
end