Re: [Caml-list] Forcing a Map type: setting the value type

[David MENTRE <dmentre@linux-france.org>]

Hello Hugo,

2011/5/2 Hugo Ferreira <hmf@inescporto.pt>:
> Maybe I did not express myself correctly.
> The above would also work with any other type for the
> parameter 'a. I want only integers for it. So:
>
> # let m = IntMap.empty;;

Just do:

 # let m : int IntMap.t = IntMap.empty;;

The " : int IntMap.t" type annotation restricts the default "'a
IntMap.t" of IntMap.empty.

> # let m = IntMap.add 1 "42" m;;

Then:

 # let m = IntMap.add 1 "42" m;;
Characters 26-27:
  let m = IntMap.add 1 "42" m;;
                            ^
This expression has type int IntMap.t but is here used with type
  string IntMap.t


Best regards,
david