bootstrap.lua

local function w_render()
    local self = {}

    local onrender_cb

    function self.onrender(cb)
        onrender_cb = cb
    end

    function self.render()
        onrender_cb()
    end

    return self
end


local w = w_render('value')

w:onrender(function()
    print('onrender')
end)

w:render()