Re: [boost] Boost Units library preview

From: Andy Little (andy_at_[hidden])
Date: 2006-08-29 15:31:03

"Jeff Garland" <jeff_at_[hidden]> wrote in message
news:44F48A27.5060908_at_crystalclearsoftware.com...
> Andy Little wrote:
>> "Jeff Garland" <jeff_at_[hidden]> wrote in message
>> news:44F4796E.4030406_at_crystalclearsoftware.com...
>>> Just to give you the flavor of how this actually needs to look, here's some
>>> code to output a 'date duration' type:
>>>
>>>...snip details...
>>>
>>> As you can see it's reasonably complex to output what amounts to an integer
>>> across wide streams and with customizeable formats.  But really, output is
>>> trivial compared to input.
>>
>> I also think that this is kind of funny. On the one hand you provide the
>> pretty
>> complex code just to output a date, OTOH it seems that the Boost.Units ( not
>> now
>> physical units afaics, certainly not Quan anyway) library is now required to
>
> I didn't say it was required...just trying to raise the bar and get the
> library to do something truly revolutionary and useful :-)

FWIW Quan already provides comprehensive support for dealing with physical
quantities. AFAICS the recent spate of Units libraries is very much based on the
PQS review, and PQS was the result of a great deal of original work in trying to
identify and solve problems in the physical quantity domain. Note that all the
current proposals basically lay out a quantity as Quan does, and this was
innovated in PQS, a break from the previous approach , all then based on SI
Units.  Unfortunately nothing I have seen has anything like the functionality
already available in Quan. I too could make claims that Quan 'is going to do X
and Y at some unspecified time'. I don't do that. I prefer to show what I have
already achieved, demonstrated, proven, tested and what is working and available
now for use. I don't see much benefit in discussing 'visionary vapourware'
without at least some use cases and preferable some code,tests and docs.

As far as being useful, the feedback I have had suggest that those that have
tried out the library have found it very useful.

>> provide a generic output for
>> any unit, including AFAICS, money, physical quantities, network data, not
>> forgetting apples and oranges, per hour of course. and presumably with as
>> much
>> flexibility on each entity as the above.
>>
>> Good luck with that !
>
> If it isn't hard, it isn't worth doing, right?  I can write the 'braindead'
> one liner version of operator<<() -- why depend on a library for that?  Maybe
> I'm wrong, but that's what I thought I read as being proposed. I believe it
> can be done and you could probably steal much of the code from date-time to do
> it. 99% of of the code doesn't really depend on what is being output/input.
> But first you have to have the vision that it's needed...I'm trying to help
> with the vision thing ;-)

Great., now... Show Me The Code!

regards
Andy Little