Jacques Garrigue wrote:
> 
> In this case, I suppose we should read `%' as `is'.
> 

>         Objective Caml version 2.99+10
> 
> # List.map;;
> - : fun%('a -> 'b) -> 'a list -> 'b list = <fun>
> # List.map [1;2;3] fun%succ;;
> - : int list = [2; 3; 4]
> # let sub ?(%pos = 0) ?%len s =
>     let len = match len with Some x -> x | None -> String.length s - pos in
>     String.sub %pos %len s;;
> val sub : ?pos%int -> ?len%int -> string -> string = <fun>
> 

I really do think that it looks better !

You could continue to use ":" in types: because you are giving
information about the type of a label. this would make

# List.map;;
- : fun:('a -> 'b) -> 'a list -> 'b list = <fun>
# List.map [1;2;3] fun%succ;;
 - : int list = [2; 3; 4]
# let sub ?(%pos = 0) ?%len s =
    let len = match len with Some x -> x | None -> String.length s - pos
in
    String.sub %pos %len s;;
val sub : ?pos:int -> ?len:int -> string -> string = <fun>

-- 
Christophe Raffalli
Université de Savoie
Batiment Le Chablais, bureau 21
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tél: (33) 4 79 75 81 03
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