In case Dirk is feeling lonely, I'll side with him.
I think the ultimate issue is abstraction versus
application. In a purely abstract setting, then I
agree that `-`(1, 3) should be negative. But we
don't have a purely abstract setting. I agree with
Dirk's New Year's/Easter example -- if the dates are
in order, then the diff should be positive to my
mind.
Note also:
[1] 2
Pat
On 02/04/2013 15:33, Romain Francois wrote:
Le 30/03/13 00:44, Dirk Eddelbuettel a ?crit :
On 29 March 2013 at 23:37, Robin Girard wrote:
| Hi List
|
| why is it that we have in the Datetime definition
| (here
http://dirk.eddelbuettel.com/code/rcpp/html/Date_8cpp_source.html#l00271
)
|
| double operator-(const Datetime& d1, const Datetime& d2) { return
d2.m_dt - d1.m_dt; }
| bool operator<(const Datetime &d1, const Datetime& d2) { return
d1.m_dt < d2.m_dt; }
|
| I feel there is a contradiction
| substraction shoulb be d1.m_dt - d2.m_dt; no ?
It's been a while since I wrote that and I think I followed the
difftime()
convention in R. Or maybe not. To me d1 comes before d2 in the way the
arguments are given, so d2 is larger and I want to subtract d1 from d2.
In any event, if it bugs you greatly you are always free to write your
own
function. ;-)
Dirk
wtf. This is the same as saying 3-1 = -2
And if i follow your logic, why is the operator< implemented this way
(correctly this time).
| Robin
|
| Dr. Girard Robin
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