Question

Hey guys, just wondering why ain’t my menu working, I’ve been coding it for like 8 hours now and just can’t figure out what’s wrong.

Menu = {
    label = "Mahin Menu",
    current = current or true,
    open = open or true,
    subMenus = {}
}

function Menu.newSubMenu()
    return {
        setup = Menu.setup,
        print = Menu.print,
        toggleOpen = Menu.toggleOpen,
        getCurrentMenu = Menu.getCurrentMenu,
        getLastMenu = Menu.getLastMenu,
        getNextMenu = Menu.getNextMenu,
        getPrevMenu = Menu.getPrevMenu
    }
end

function Menu:setup(m_parent, m_label, m_action)
    self.parent = m_parent
    self.label = m_label
    self.action = m_action
    self.subMenus = {}
    self.current = false
    self.open = false
    table.insert(m_parent.subMenus, self)
end

function Menu:print(indent)
    io.write(string.rep("    ", indent))
    if #self.subMenus>0 then
        if self.open == true then
            io.write("[-]")
        else
            io.write("[+]")
        end
    else
        io.write("   ")
    end
    if self.current == true then
        io.write("<" .. self.label .. ">")
    else
        io.write(" " .. self.label)
    end
    io.write("\n")
    if #self.subMenus>0 and self.open == true then
        for i=1,#self.subMenus do
            self.subMenus[i]:print(indent+1)
        end
    end
end

function Menu:toggleOpen()
    if self.open == true then
        self.open = false
    else
        self.open = true
    end
end

function Menu:getCurrentMenu()
    if self.current == true then
        return self
    else
        for k=1,#self.subMenus do
            local v = self.subMenus[k]:getCurrentMenu()
            if v ~= nil then
                return v
            end
        end
    end
end

function Menu:getLastMenu()
    if self.open == true and #self.subMenus > 0 then
        return self.subMenus[#self.subMenus]:getLastMenu()
    else
        return self
    end
end

function Menu:getNextMenu(bool)
    bool = bool or false
    if bool == false then
        if #self.subMenus > 0 and self.open == true then
            return self.subMenus[1]
        end
    end
    if self.parent then
        if self.parent.subMenus[#self.parent.subMenus] == self then
            self.parent:getNextMenu(true)
        else
            for i=1,#self.parent.subMenus do
                if self.parent.subMenus[i] == self then
                    print(self.parent.subMenus[i+1].label)
                    return self.parent.subMenus[i+1]
                end
            end
        end
    else
        return self
    end
end

function Menu:getPrevMenu()
    if self.parent then
        for k=1,#self.parent.subMenus do
            if self.parent.subMenus[k] == self then
                if k == 1 then
                    return self.parent
                elseif #self.parent.subMenus[k-1].subMenus > 0 and self.parent.subMenus[k-1].open == true then
                    local x = self.parent.subMenus[k-1]
                    while #x.subMenus > 0 and x.open == true do
                        x = x.subMenus[#x.subMenus]
                    end
                    return x
                else
                    return self.parent.subMenus[k-1]
                end
            end
        end
    else
        return self
    end
end

Test = Menu.newSubMenu()
Test:setup(Menu, "Test item")
Mahi = Menu.newSubMenu()
Mahi:setup(Menu, "Mahi item")
Mahi.open = true
Testx = Menu.newSubMenu()
Testx:setup(Mahi, "Lalall")
Testx.open= true
Sadmad = Menu.newSubMenu()
Sadmad:setup(Testx, "Woot")
Asd = Menu.newSubMenu()
Asd:setup(Menu, "Asd menu")
Asd.current = true
Menu.current = false

repeat
    print(string.rep("\n",2))
    Menu:print(0)
    x=io.read()
    if x == "z" then
        x = Menu:getCurrentMenu()
        print(Menu:getCurrentMenu().label)
        print(Menu:getCurrentMenu():getNextMenu().label)
        y = Menu:getCurrentMenu():getNextMenu()
        x.current = false
        y.current = true
    elseif x == "a" then
        x = Menu:getCurrentMenu()
        y = Menu:getCurrentMenu():getPrevMenu()
        x.current = false
        y.current = true
    end
until x == "sad"

”
there’s the code, and when ever i try to move my current from “Asd menu” downwards, it’ll error:

menu.lua:150: attempt to index a nil value

which doesn’t make any sense, it’s clearly declared, and I’ve tried adding prints and they always give me Asd menu O.o
Same goes for if I’ll try to move from Woot to Asd menu, same exact error, and I have no idea why, since I added those prints

print(Menu:getCurrentMenu().label)
print(Menu:getCurrentMenu():getNextMenu().label)

and they do give me Asd menu, but then it says that trying to index a nil value at the second print line, but it sill does print? I’m out of ideas, any help out here?

Answer 1

You are missing a return statement in line 92.

Note that this line does not actually return anything, so the function is returning nil.
After changing it to return self.parent:getNextMenu(true) it seems to be working.