Option 2: the goal is to eventually eliminate ParentWithGens and ParentWithBase, and rewrite all classes in Sage that use their functionality to instead use the functions defined by sage.structure.parent.Parent and sage.structure.category_object.CategoryObject.
This transition will take quite a bit of work. We tried doing it all at once at a Sage Days a year and a half ago and failed. Instead, there's now a framework set up to enable doing the transition gradually, one class at a time. The currently favored framework is described at http://wiki.sagemath.org/coercion (more details can be obtained by looking at the reference manual pages on sage/structure/parent.pyx, sage/structure/coerce.pyx, sage/structure/coerce_actions.pyx, sage/structure/coerce_maps.pyx). Note that the provided methods described there (__call__, get_action, has_coerce_map_from, etc), generally won't work if you're inheriting from a parent that doesn't comply with the new system (for example, it might define it's own __call__ method, making your _element_constructor_ never be called). The ticket setting up the transition framework is at http://trac.sagemath.org/sage_trac/ticket/3738. What I couldn't find just by googling was a guide for converting old parents to the new style. I think that there are a number of people who could write such a document: if you want to help me put it together, let me know. The difficulty varies quite a bit: most are going to be easy (with the obstruction mainly the sheer number of changes to make), and some are trickier. Once I have something that's coherent to people who aren't already familiar with the coercion system, I'll put it on the wiki and e-mail the list. David On Fri, Feb 12, 2010 at 5:14 PM, Andrey Novoseltsev <novos...@gmail.com>wrote: > Hello, > > I have started writing a class for Fano toric varieties, and as I > understand it should inherit from AmbientSpace. Going further, > AmbientSpace derives from ParentWithGens and in the beginning of the > corresponding file we see > > .. note:: > > This class is being deprecated, see > ``sage.structure.parent.Parent`` and > ``sage.structure.category_object.CategoryObject`` for the new > model. > > Does it mean that all NEW classes in Sage have to derive from these > ones, or the goal is also to eventually rewrite OLD classes derived > from ParentWithGens to use the new model too? In particular, is it > desirable to make AmbientSpace derived from Parent? > > Thank you, > Andrey > > -- > To post to this group, send an email to sage-devel@googlegroups.com > To unsubscribe from this group, send an email to > sage-devel+unsubscr...@googlegroups.com<sage-devel%2bunsubscr...@googlegroups.com> > For more options, visit this group at > http://groups.google.com/group/sage-devel > URL: http://www.sagemath.org > -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
