[m-rev.] for review: Improve `integer' module interface.

[Julien Fischer]

Hi Peter,

On Fri, 13 Feb 2015, Peter Wang wrote:

> Add integer.to_int/2 which fails instead of throwing an exception if the
> value cannot be represented as an `int'.
>
> Deprecate semidet functions:
> 	from_string/1, from_base_string/2, int/1
>
> Add semidet predicates to replace them:
> 	from_string/2, from_base_string/3, det_to_int/1

det_to_int/1 is not a predicate, nor is it semidet.

>
> library/integer.m:
> 	As above.
>
> library/string.format.m:
> 	Conform to changes.
>
> NEWS:
> 	Announce changes.
>
> * The following predicates and functions have been added to the require module:
>
>    - error/2
> diff --git a/library/integer.m b/library/integer.m
> index 4312c33..eb962be 100644
> --- a/library/integer.m
> +++ b/library/integer.m

....

> @@ -1038,17 +1055,21 @@ float_list(_, Accum, []) = Accum.
> float_list(FBase, Accum, [H | T]) =
>     float_list(FBase, Accum * FBase + float.float(H), T).
>
> -integer.int(Integer) = Int :-
> -    (
> -        Integer >= integer(int.min_int),
> -        Integer =< integer(int.max_int)
> -    ->
> -        Integer = i(_Sign, Digits),
> -        Int = int_list(Digits, 0)
> +integer.to_int(Integer, Int) :-
> +    Integer >= integer(int.min_int),
> +    Integer =< integer(int.max_int),
> +    Integer = i(_Sign, Digits),
> +    Int = int_list(Digits, 0).
> +
> +integer.det_to_int(Integer) = Int :-
> +    ( integer.to_int(Integer, IntPrime) ->
> +        Int = IntPrime
>     ;
>         error("integer.int: domain error (conversion would overflow)")
>     ).

s/integer\.int/integer\.det_to_int/ in the error message there.

The change looks fine otherwise.

Cheers,
Julien.