How to change a module's upvalue?

[俞江 <devyujiang@...>]

Hi all!

    There is a module 'a.lua':

local num = 1

function print_num()

    print(num)

end

     

     And used as:

A = require('a')

    I want to change the 'num' to 10 in the runtime, but

load("local num=100",nil,nil,A)() 

load("num=100",nil,nil,A)()

    does not work, how to do it?