| -----Original Message----- | From: boost-bounces@lists.boost.org | [mailto:boost-bounces@lists.boost.org] On Behalf Of Simon Buchan | Sent: 26 October 2005 00:28 | To: boost@lists.boost.org | Subject: Re: [boost] Interest in dimension/unit-checking library? | >... | not to mention the ones *I* had yet to conceive ;-) | | Don't forget the particle/quantam guys! Their units under-flow SI | doubles! (Or at least loose some serious accuracy) | > I worry that the compile times and complexity will outstrip | both hardware | > and compilers, but the only way to find out is to try it. | So I would | > encourage Matt to continue his efforts in this direction. | > | A lot of time could be saved with good header design, I assume, but | there really is no way around some overhead. Maybe some sort of | explicit instatiation and static linking stategy (whether in user or | library) could help. Some VERY fancy meta-coding is required but the compile time effect on real-life projects remains difficult to predict. | > Paul | > | > PS My gut instinct is to enforce explicit conversions - | mainly as a matter | > of documenting intent, but I am just about persuaded that | implicit can be | > OK, provided it is loseless. | > If we can have a way of highlighting when implicit | conversion takes place, | > that could make everyone happier. | > | Implicit lossy conversions are the worst curse a library can | inflict on | the user, IMAO. Lossless is better, but I am only comfortable with | promotions, I don't even like int to double very much (as it | loses the guarantee of integralness). | So yes, explicit only. We are talking about implicit conversions from feet to meters here - almost certainly lossless. You need to read Matt's quite complicated arguments for these. | Try putting the line "-- " just before this, it marks this as | a sig, so | it won't be quoted in a lot of agents (AFAIK): | > Paul A Bristow | > Prizet Farmhouse, Kendal, Cumbria UK LA8 8AB | > Phone and SMS text +44 1539 561830, Mobile and SMS text +44 | 7714 330204 | > mailto: pbristow@hetp.u-net.com www.hetp.u-net.com Does this please you better? -- Paul A Bristow Prizet Farmhouse, Kendal, Cumbria UK LA8 8AB Phone and SMS text +44 1539 561830, Mobile and SMS text +44 7714 330204 mailto: pbristow@hetp.u-net.com www.hetp.u-net.com