let
next
(
Delay
s
) =
s
()
let
tl
s
=
snd
(
next
s
)
let
rec
first
s
k
=
if
k
> 0
then
let
h
,
t
=
next
s
in
h
::
first
t
(
pred
k
)
else
[]
let
l
=
first
entiers
13;;