<div dir="ltr"><div><div><div><div><div>Maybe not surprisingly, I favor Walter's proposal.<br></div>It has the distinct advantage that it is extensible<br></div>and does not paint us into a corner.<br></div><div>For instance, at some point the need may arise<br>for distances in Cartesian coordinates<br>(3-D spatial distances).<br></div></div><br></div> - Arnold<br></div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature"><div dir="ltr">-------------------------------------------------------------------------------------------------------------<br>Arnold H. Rots Chandra X-ray Science Center<br>Smithsonian Astrophysical Observatory tel: +1 617 496 7701<br>60 Garden Street, MS 67 fax: +1 617 495 7356<br>Cambridge, MA 02138 <a href="mailto:arots@cfa.harvard.edu" target="_blank">arots@cfa.harvard.edu</a><br>USA <a href="http://hea-www.harvard.edu/~arots/" target="_blank">http://hea-www.harvard.edu/~arots/</a><br>--------------------------------------------------------------------------------------------------------------<br><br></div></div></div>
<br><div class="gmail_quote">On Thu, Apr 7, 2016 at 4:43 AM, Markus Demleitner <span dir="ltr"><<a href="mailto:msdemlei@ari.uni-heidelberg.de" target="_blank">msdemlei@ari.uni-heidelberg.de</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi Walter,<br>
<span class=""><br>
On Wed, Apr 06, 2016 at 11:14:17AM -0700, Walter Landry wrote:<br>
> Marco Molinaro <<a href="mailto:molinaro@oats.inaf.it">molinaro@oats.inaf.it</a>> wrote:<br>
><br>
> Since no one commented on it before, I would like to repeat my<br>
> proposal for a point literal.<br>
><br>
> {a,b} -> POINT('ICRS GEOCENTER',a,b)<br>
><br>
> Then the distance function would be<br>
><br>
> DISTANCE({ra1,dec1},{ra2,dec2})<br>
><br>
> This would keep the function type safe and obviate the need for a new<br>
> overload for DISTANCE.<br>
<br>
</span>I suppose everyone was more or less like me: Nice, but is it really<br>
worth introducing new syntax? And will this be trouble later, when<br>
we (perhaps) may deal with array literals? Not sure. Ah, let<br>
someone else worry about it.<br>
<br>
So, I can't give you more than a heartfelt "undecided".<br>
<br>
<br>
DISTANCE with four floating-point arguments, on the other hand, sits<br>
nicely in my comfort zone of probably making the average astronomer<br>
happy while being very cheap -- after all, we have other functions<br>
that admit a variable number of arguments and change behaviour<br>
depending on the arity used. I'll just mention random here.<br>
<br>
Cheers,<br>
<br>
Markus<br>
</blockquote></div><br></div>