Trying to Cycle Pages

Hello,
I'm trying to create a list of pages to load with the touchpoint API and then cycle through them so I can scroll through the pages like the next or previous buttons in an online book. Here is the basic code I am trying to get to work:

os.loadAPI("touchpoint")
monitor = peripheral.wrap("left")

local a = touchpoint.new("left")
local b = touchpoint.new("left")
local currentPage = a

function nextPage()
  local pageList = 'ab'
  local index = pageList:find(currentPage)
  if index then
	currentPage = index + 1
  end
  currentPage:draw()
end

a:add("--->", function() nextPage() end, 1, 1, 10, 10, colors.red, colors.green)
b:add("placeholder", nil, 1 ,1 , 10, 10, colors.red, colors.green)
currentPage:draw()
currentPage:run()

When I try to run the code it draws the first button and sets up the pages. However, when I try to click the button and proceed to the next page, it gives an error saying that on line 10, it is expecting a string but receiving a table. I do not know how to convert what the current page is into a string so it can run. I have tried using concat and serialize/unserialize, but neither way works and I'm not sure how to do it. Thank you.

You should put your pages in a table, then use a numeric index to point at the current page. You also won't be able to use the :run() method on the pages, since it will never change which one is being run.

local pages = {
  touchpoint.new("left"),
  touchpoint.new("left"),
}

local index = 1

local function nextPage()
  index = math.min(index + 1, #pages)
end

local function prevPage()
  index = math.max(index - 1, 1)
end

page[1]:add("--->", nextPage, 1, 1, 10, 10, colors.red, colors.green)
page[2]:add("<---", prevPage, 1, 1, 10, 10, colors.red, colors.green)

while true do
  pages[index]:draw()
  local event = {pages[index]:handleEvents(os.pullEvent())}
  if event[1] == "button_click" then
    if pages[index].buttonlist[event[2]].func then
      pages[index].buttonlist[event[2]].func()
    end
  end
end

Or something like that.

Thank you so much for the response! I appreciate it. I tried using the code you pasted, and it gives an error regarding the line with the second if statement (line 23 of your example), saying it is trying to index a nil value. Would you be able to explain why it is doing that and possibly how to fix it? Thank you.

That line and the line below it should have buttonList where they have buttonlist.

Thank you so much for the help! That was the indeed the problem. Happy New Years.