[m-rev.] for review: implement checked division for uints

[Julien Fischer]

Hi Peter,

On Thu, 11 May 2017, Peter Wang wrote:

> On Wed, 10 May 2017 13:10:07 +1000 (AEST), Julien Fischer <jfischer at opturion.com> wrote:
>>
>> For review by anyone.
>>
>> The int module also provides div/2 and mod/2 which round differently for
>> negative results than / and rem.  The result cannot (obviously) be
>> negative for uints; do we want to provide div/2 and mod/2 as synonyms for
>> / and rem in the uint module?  (mod in particular is the obvious name
>> for the operation.)
>
> I think so, especially mod.

Done.

>> Note: I will update the expected output for 32-bit system before I
>> commit.
>>
>> -----------------------------
>>
>> Implement checked division for uints.
>>
>> library/uint.m:
>>       Add (//)/2, (/)/2 and rem/2 for uints.
>>
>> tests/hard_coded/uint_arith.m
>>       Enable the division tests.
>>
>> tests/hard_coded/uint_bitwise.exp:
>>       Update the expected output.
>>
>> Julien.
>>
>> diff --git a/library/uint.m b/library/uint.m
>> index f757cd78e..a0088ab36 100644
>> --- a/library/uint.m
>> +++ b/library/uint.m
>> @@ -77,8 +77,31 @@
>>       %
>>   :- func min(uint, uint) = uint.
>>
>> +    % Integer division.
>> +    %
>> +    % Throws a `math.domain_error' exception if the right operand is zero.
>> +    %
>> +:- func (uint::in) // (uint::in) = (uint::uo) is det.
>
> int.m specifies "Truncating" integer division

I've added that here too.

Julien.