From now on, instead of showing the actual OCaml session…
OCaml
# let rec factorial a =
if a = 1 then 1 else a * factorial (a - 1);;
val factorial : int -> int = <fun>
…we will usually just show the program in a box, together with its type:
If you prefer to compose your programs in a text editing program, and
copy-and-paste them into OCaml, you can do that too. Just make sure you
end with ;; to let OCaml know you have finished entering
the program.
Later on, when we write larger programs, we will see how to use OCaml to load our programs from external files.