On 2011/07/05, at 22:59, malc wrote:
> Perhaps someone could explain why following behaves the way it does:
>
> ~$ ocaml
> Objective Caml version 3.11.2
>
> # let f ic = let i = input_value ic in let j = i + 1 in LargeFile.seek_in ic
> i;;
> Warning Y: unused variable j.
> val f : in_channel -> unit = <fun>
The return type of input_value being 'a, which gets generalized by the
relaxed value restriction, i gets the polymorphic type "forall 'a. 'a".
So you can use it both as an int and an int64.
==> input_value is an unsafe function, you should always write a type
annotation on its return type.
> # let f ic = let i = input_value ic in let j = i + 1 in LargeFile.seek_in ic
> j;;
> Error: This expression has type int but an expression was expected of type
> int64
j being the result of an integer addition, it has type int, and cannot be used
as int64.
Jacques
--
Caml-list mailing list. Subscription management and archives:
https://sympa-roc.inria.fr/wws/info/caml-list
Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
Bug reports: http://caml.inria.fr/bin/caml-bugs
