On 2015-11-23 14:24, Eric Gourgoulhon wrote:
Hi,Le lundi 23 novembre 2015 10:55:40 UTC+1, Jeroen Demeyer a écrit : Of course, you could argue that Element should not have __add__ and __mul__ (since not all elements can be added or multiplied). But it doesn't really hurt to have them and raise NotImplementedError (unless I'm missing something). Maybe a too naive remark: what you propose seems against standard object-oriented programming. Isn't it more clear to have a generic base class Element and implement __add__ and __mul__ only in derived classes, when relevant?
I get your point, but it's not black or white: we need to look at advantages and disadvantages of having so many classes. One problem with your "object-oriented programming" comment is that we cannot have multiple inheritance for these classes, since they are extension types (a.k.a. cdef classes). So we need to reimplement certain methods several times. Then there is also some performance overhead of having all these different classes.
The names are also confusing: isinstance(x, FieldElement) is *not* a good way to check if x is in a field. We have the category framework for that.
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