Re: [Caml-list] Random.self_init in Jane Street Core

[Martin Jambon <martin.jambon@ens-lyon.org>]

On Wed 21 May 2014 05:28:00 AM PDT, David House wrote:
> Relatedly, one should be careful using the [ignore] function. Always
> give its argument a type signature. E.g. if you do this:
>
>   ignore (my_function foo);
>
> Then this will start silently not calling [my_function] whenever
> someone adds a second argument. You should instead use:
>
>   ignore (my_function foo : Foo.t);

I think it used to be a problem but it no longer is. Recent versions of 
OCaml give a warning when passing a function, so there's no need for a 
type annotation:

$ ocaml
        OCaml version 4.01.0

# ignore print_endline;;
Warning 5: this function application is partial,
maybe some arguments are missing.
- : unit = ()


>
> On 21 May 2014 13:25, Ollie Frolovs
> <ollie.frolovs.2012@my.bristol.ac.uk
> <mailto:ollie.frolovs.2012@my.bristol.ac.uk>> wrote:
>
>     oh dear! i think i know what happened. self_init has never been
>     called in the first place! it requires a unit argument which i did
>     not give it, so the “alias” to Random.self_init was assigned to
>     nothing, so to speak, instead of calling the function.
>
>     Many thanks, Dmitry! I’ve amended that line to let () =
>     Random.self_init () and it works.
>
>     On 21 May 2014, at 13:18, Dmitry Grebeniuk <gdsfh1@gmail.com
>     <mailto:gdsfh1@gmail.com>> wrote:
>
>     > Hello.
>     >
>     >> let _ = Random.self_init
>     >
>     >  That's why I almost never use "let _ = ...", or
>     > constrain "_" to some type when I use it.
>     >  Try to replace it with "let () = ..." and follow compiler
>     > errors.  Or with "let (_ : unit) = ...".
>
>
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