ERROR: lua: simpleApp1.lua:1: attempt to index global 'fltk' (a nil value)

[Shamun toha md <shamun.toha@...>]

I have a strange problem with this fltk line 5 says: 

# lua simpleApp1.lua 

lua: simpleApp1.lua:1: attempt to index global 'fltk' (a nil value)

stack traceback:

simpleApp1.lua:1: in main chunk

[C]: ?

# 

$ cat simpleApp1.lua 

  do local object = fltk:Fl_Double_Window(166, 165, "My App");

    window = object;

    fltk:Fl_Return_Button(5, 130, 155, 30, "A return button");

    myOptions = fltk:Fl_Check_Browser(5, 5, 155, 70, "Some choices");

    myField = fltk:Fl_Input(5, 95, 155, 30);

    myOptions:add("Shower and shave") 

    myOptions:add("Breakfast") 

    myOptions:add("Watch TV") 

    myOptions:add("Go to work") 

    myOptions:add("Call the plumber")

    

    myField:callback(

      function(myField)

          fltk.fl_message("Changed the value to \"" .. myField:value() .. "\"")

    end)

  end

  window:show();

  Fl:run();