> On Jan 14, 2017, at 3:54 AM, Geert Janssens <[email protected]> > wrote: > > Hi, > > The last few days I have payed some attention to our Travis-CI integration. > Good news is we can > now run our unit tests based on google test (thanks to John as well for some > extra fixes). > > The bad news is my csv-import work fails to build on travis while it builds > just fine on my local > system. The most recent build failure can be seen here: > > https://travis-ci.org/gjanssens/gnucash/builds/191881753 > > This has been failing for a while, even before fixing the gtest stuff. My > investigation seems to > suggest the issues stems from using a different version of boost on my system > (1.60.0) versus > the one used on travis (1.54.0). > > The failure is in this line: > if ((m_deposit == boost::none) && > (m_withdrawal == boost::none)) > with both m_deposit and m_withdrawal being of type > boost::optional<gnc_numeric>. > It appears boost 1.54.0 doesn't know how to run this comparison and the > boost::optional > revision history suggests this was addressed in version 1.56.0 [1]. > > Since our boost baseline is still 1.53.0, I'm looking for ways to handle this > differently. > gnc_numeric is a C struct. My csv-importer work however is all in c++, so why > not use the > underlying c++ code of gnc_numeric directly, right ? > > So I am working my way through this and have some questions about this. > > 1. I assumed the C++ equivalent of gnc_numeric would be GncNumeric. However > this appears > to be wrong assumption. GncNumeric is only defined as an alias inside > gnc-numeric.cpp and > hence not exposed at all to the outside world. Is new c++ code not supposed > to use > GncNumeric ? Should GncRational be used directly instead ? > > 2. I continued with GncRational for now. However this seems to implement only > fairly limited > subset of the functions in gnc_numeric. For example there is gnc_numeric_mul > and > GncRational::mul. The former takes two extra parameters (one for denom > preference and one to > tell how to round). GncRational::mul on the other hand takes a denom object > as second > parameter which encapsulates all that information in addition to the two > objects we're about to > multiply. I'm not sure how I should use this. Should each consumer of the > GncRational class > each time build the denom object itself and then call the GncRational > mutators ? That looks like > a lot of code overhead. How about an overload for these mutators that takes > the denom and > round type directly as gnc_numeric_mul does ? Or is there another way to use > this I didn't figure > out yet ? > > 3. While studying the GncRational code I noted it has doesn't specify the > pure constructor > "GncRational()", instead leaving this up to the compiler to generate if > necessary. That compiler > default would create a GncRational with m_num = 0, m_denom = 0 and m_error = > GNC_ERROR_OK. I would consider > m_num = 0, m_denom = 1 and m_error = GNC_ERROR_OK a better default value for > GncRational. A particular reason not to implement that ?
Geert, Thanks for the (somewhat belated) code review! Yes, GncRational is at this point incomplete. I did the minimum I could to get rid of the computational limitations of gnc_numeric and left a lot of functionality to be implemented later as needed on the grounds that gnc_numeric has what appears to be duplicated interface. My plan is to use GncRational in new C++ code and implement addtional functions as needed; it wasn't my plan that you'd be the first to be doing that. GncDenom exists to separate the rounding action from GncRational. Looking at it again after a year I see that I should make round() a GncDenom member function, which would allow templating it and so getting rid of the switch and permitting faster compile-time dispatch. A second flaw that I see now is that the arithmetic functions shouldn't be doing the rounding; that would allow replacing them with the full set of operators, a far more natural interface *and* better practice because it permits postponing the rounding operation to the end of a chain of calculations. The reason I exposed GncDenom outside of GncRational was that it seems to be common in usage to have a bunch of calculations using the same rounding parameters, so the idea was that one could create a single GncDenom and pass it around to all of the operations. C++ overloading makes it easy to have that cake and to eat it by providing template <class GD> GncRational::round(const GD&) (where GD is a specialization on RoundType) and GncRational::round(DenomType, RoundType) which creates the GncDenom and calls the template version. You're absolutely right about the default constructor. Regards, John Ralls _______________________________________________ gnucash-devel mailing list [email protected] https://lists.gnucash.org/mailman/listinfo/gnucash-devel
