Some comments: Non-underscore attributes implement a mutable interface. You are inviting your users to modify field.tensor_type = (1,2), which will almost certanly lead to inconsistent objects. In Sage, the convention is generally to use underscore attributes and ensure immutability through accessor methods. An alternative would be read-only attributes, but this is generally not used in Sage.
The split ScalarField <-> ZeroScalarField duplicates value information in the type. This is awkward for the implementation where you always have to check and make sure that algebraic operations don't accidentally create a ScalarField that happens to be zero. If you really need to be able to tell quickly if a field is zero just cache .is_zero() -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
