Re: [boost] [units] Interest in UDLs (e.g. _kg) for units?

25 Aug 2014


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From: Mathias Gaunard 
To: boost@lists.boost.org
Date: Mon, 25 Aug 2014 17:16:21 +0200
Subject: Re: [boost] [units] Interest in UDLs (e.g. _kg) for units?
On 25/08/14 16:03, Sebastian Redl wrote:
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On 25 Aug 2014, at 13:24, Mathias Gaunard 
wrote:
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On 22/08/14 10:08, Curdeius Curdeius wrote:
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Hi all,
I was wondering if there is any interest in adding User-Defined
Literals
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(UDLs) to Boost.Units.
IMO, it could simplify some code and improve code readability in some
cases.
For example instead of writing (it's a somehow artificial example)
     5.34 * si::milli * si::kilogram;
     1234 * si::kilogram;
one would write
     5.34_g;
     1234_kg;
Did you mean to write
5.34_g * si::milli;
or
5.34_mg;
?
No, to get grams you need si::milli * si::kilogram. I assume the
intention is that the _g suffix already includes that scaling - otherwise
it’d be broken.
Sorry, I read that too fast.
In any case the idea would be to get suffixes that include all prefix
variants as well.
Yes, the idea is to include all the prefix variants as well, so for the
mass, we will have:
..., _ng, _ug (?), _mg, _g, _kg, _Mg,_Gg, _Tg, ...
And, the fact is, writing si::milli * si::kilogram is counterintuitive as
you have just experienced on your own.

Marek Kurdej
--
Ph.D. candidate