[boost] Re: Compile-time of unit-libraries

From: Daniel Frey (daniel.frey_at_[hidden])
Date: 2004-01-13 02:56:03

Matthias Schabel wrote:
>> PS: Matthias' example idealGasLaw() sent my constant library back to  
>> the design phase (*sigh*). The main problem is the lack of typeof,  
>> even the currently available extensions from GCC and the  
>> Intel-compiler (__typeof__) only give me internal compiler errors :(
> 
> Sorry...the whole library also has an unfortunate  tendency to send  
> compilers to the graveyard...  BTW, when you get the gcc people to put  
> in typeof, please put in a request for template typedefs for me ;^)

:)) I know that tendency, as it's the same for the constant library. At 
least I can support GCC3 and the Intel compiler (thus, hopefully, EDG in 
general), but no VC support yet. I was able to solve the __typeof__ 
problems, but there's still a lot to do. In fact, I think that there is 
a component which should be shared between the unit and the constant 
library: Result type deduction/selection for mixed arithmetics.

> You should be able to use the 2.2 version for now.  I'm going to fix up  
> some stuff, add changes in static_rational that Andy and Jan have  
> suggested and maybe a bit more, but it will probably be a week or two  
> before I have anything concrete.  BTW, I'm thinking about decoupling  
> units from systems, so instead of declarations like :
> 
> SI<double>::length
> 
> you'd have
> 
> quantity<SI,length,double>

Sounds good, although some helpers might be necessary to provide a nice 
syntax.

> Does that have design ramifications for the constants library?

Don't know yet, I'll look at it when I find the time. As I said above, 
some of the component might be needed for both libraries, but currently 
all I have is some ideas, no code yet.

Regards, Daniel

-- 
Daniel Frey
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