event1=class()
function event1:paint(gc)
   gc:drawString("XX",x1,y1)
timer.start(0.1)
end
function event1:timer()
   x1=x1+1
   y1=y1+1
platform.window.invalidate()
end

event2=class()
function event2:paint(gc)
   gc:drawString("XXX",x2,y2)
timer.start(1)
end
function event2:timer()
   x2=x2+1
   y2=y2+1
platform.window.invalidate()
end

function on.paint(gc)
 event1():paint(gc)
 event2():paint(gc)
end
function on.timer()
 event1():timer()
 event2():timer()
end


------you know, it doesn't work. what should l do?

You forgot to define event1:init() and event2:init(), and then, you forgot to call them once.

This is a restriction of using class(), you may define a constructor, and call it to create the object

what should l write in event:init() ?

Nothing, if you don't need so.

Actually, class() seperates the meta-tables and creates a new one to let you call event1 as a specific class. init() initializes the meta-table.
class() is not part of Lua, it is part of the TI Nspire framework, thus, it computerizes some routines to represent classes in Lua, even if it is not an object oriented language.

  do you have an E-mail address ?

And, don't double post within 6 hours.