Re: functions and upvalues

["Mauro Iazzi" <mauro.iazzi@...>]

On 31/05/07, Wesley Smith <wesley.hoke@gmail.com> wrote:

You're right.  I will just have to make a table and pass it in.

Why simply not making val an argument to gen1? Arguments behave just as a local variables, if I understand correctly (i.e. they become upvalues).

Thus the code would simply be:

function gen1(val)
    return function()
        print(val)
    end
end


function constructor(generator)
    local val = 100

    return function()

       local f1 = generator(val)

       f1()

    end
end

constructor(gen1)()
-> 100

Hope it helps.

m.i.

PS: (please don't read)
if you want to have fun, 

function bind_before(f, v) return function(...) return f(v, unpack(arg)) end end
function bind_after(f, v) return function(...) return f(unpack(arg), v) end end
gen1 = bind_before(bind_before, print)
constructor = bind_after(bind_before, 100)

constructor(gen1)()()
->100

sorry for being nerdy, I could not resist.