Decimal Floating Point types.

[Sean Kelly]

On Oct 29, 2012, at 3:51 PM, "H. S. Teoh" <hsteoh at quickfur.ath.cx> wrote:

> On Mon, Oct 29, 2012 at 11:41:45PM +0100, Rob T wrote:
>> On Monday, 29 October 2012 at 18:43:36 UTC, Iain Buclaw wrote:
>>> Speaking on behalf of Dejan, he expressed a wish to have such a
>>> type in D. (eg: such that assert(3.6 * 10 == 36.0) - which may not
>>> always be true on all architectures).
>>> 
>>> 
>>> As maybe a new backend type is out of the question.  Perhaps we
>>> should create a new library type for the job - eg: _Decimal32,
>>> _Decimal64, _Decimal128.
>>> 
>>> Thoughts?
>>> 
>>> 
>>> Regards
>>> Iain.
>> 
>> I would definitely want these. They are necessary for doing math on
>> currency values.
> [...]
> 
> I thought it was better to use fixed-point with currency?

With currency, as in most other instances, you usually want to do your rounding once at the end of the calculation, or at least control exactly where and how the rounding is done.  Rounding implicitly on each step means money effectively vanishing into the ether, and people tend not to like that.