"Gerhard Wesp" wrote
Physics gives quite clear directions as to which operations a time type must support: - Addidtion, subtraction, comparison with other time's. - Division by other time's to give a dimensionless type. - Conversion to/from whatever is useful, maybe stream operators.
Note that any builtin arithmetic types support those operations, but they're not "typesafe" in the sense that you might end up e.g. adding time and length. A user-defined type can protect you from those accidents by only defining the above mentioned operations.
*If* we want a user-defined type to represent time, it may well be part of a general framework for physical quantities. See e.g. http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2003/n1451.html, section 6 for ideas on how this can be done.
BTW It might be useful to point out that my Physical Quantities library 'pqs' , which provides the above operations, is up for Formal Review by Boost at some time in the near future: http://tinyurl.com/7m5l8 (I hope that 'pqs_3_1_0' in that directory will be the review version, but that will be subject to my Review Managers approval. If all is in order then I hope that the review dates for pqs will be confirmed soon). regards Andy Little