std.experimental.checkedint is ready for comments!

[Andrei Alexandrescu via Digitalmars-d]

On 06/15/2016 02:26 PM, Walter Bright wrote:
> On 6/15/2016 9:40 AM, Andrei Alexandrescu wrote:
>> Looking at the IntFlagPolicy, it offers three canned behavior: throws,
>> asserts,
>> and noex. Users cannot customize behavior and there is no information
>> passed
>> into the policy (e.g. the operands in case of overflow, or the
>> numerator in case
>> of division by zero). Passing the appropriate information would make
>> it possible
>> to implement various policies, e.g. the policy cannot say "I'm
>> actually okay
>> with this" or "here I'll implement a saturation policy".
>
> Just a note to add to these excellent comments. One style of integer
> arithmetic is "saturation" arithmetic, whereby if it overflows, instead
> of an error it gets "stuck" at T.max. Same for underflow.
>
>    https://en.wikipedia.org/wiki/Saturation_arithmetic
>
> A good test for a policy API design is if saturation behavior could be
> done with a user-defined policy, instead of it being a pre-defined one.

Also, the proposed design mentions "hysteresis" and allows Hook to 
introduce state. -- Andrei