Re: Trivial question: how to avoid confusing sec, min, hour and day in a program?

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On 2021-09-06 09:20, ldries46 wrote:
> Op 5-9-2021 om 9:27 schreef Dmitry A. Kazakov:
>> On 2021-09-05 08:56, reinert wrote:
>>> Anybody with good ideas on how (in a simplest possible way) to avoid 
>>> to confuse between representation of time as seconds, minutes, hours 
>>> and days in an Ada program?
>>
>> Just use the standard type Duration.
>>
>>> It is somewhere in my program natural/human to think in seconds 
>>> whereas  minutes or hours feels more natural at other places (so the 
>>> numerics is "human"). Example to illustrate: heart rate is "natural" 
>>> to give in number per minute (not in number per second, hour or day). 
>>> Time on work is normally given by hours (not seconds) etc..
>>
>> The user interface is responsible to convert anything to Duration and 
>> back.
>>
> I agree with Dimitry but I think the problem  is far bigger and not only 
> in Ada but in every computer language. You cannot use packages written 
> by others if you do not know the dimensions they use. For instance in 
> mechanical engineering in Europe there is a general use of cm while in 
> other countries they use inches and in aircraft engineering they use in 
> Europe mostly mm.

Why do you need that? If written in Ada, the value is of some separate 
numeric type you could not mix with other types.

> In general the use of dimensioning system ( f.i. cgs -cm gram second) is 
> different for different countries and application area's. Some factors 
> used within calculations are even dependant in the dimensioning system.
> It would be a good idea if a package was developed that can solve all 
> these problems for instance by doing the calculations in one of the 
> possible dimensioning systems automagically presenting the results in 
> the dimension you choose.

If calculations are involved, they are performed in SI, because 
otherwise you need factors in all formulae. And SI means no mm, but m, 
no km/h, but m/s etc.

> Such a system must exist of a record for every value, that exist of at 
> least  real values for the standard dimensioning system and the value in 
> the dimensioning system you want, the factor between the two systems and 
> the string containing the dimension, perhaps even more.
> There should be functions for "+", "-", "*", "/" and sqrt.

    http://www.dmitry-kazakov.de/ada/units.htm

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de