#10667: Morphisms and Objects of Categories
---------------------------+------------------------------------------------
Reporter: SimonKing | Owner: nthiery
Type: enhancement | Status: needs_work
Priority: major | Milestone: sage-5.0
Component: categories | Keywords: objects morphisms containment
Work_issues: doctests | Upstream: N/A
Reviewer: | Author: Simon King
Merged: | Dependencies: #9138, #11115
---------------------------+------------------------------------------------
Comment(by SimonKing):
It is a very bad error, and I don't know at which point I introduced it.
It is about incompatible method resolution orders:
{{{
sage: class Foo(Homset, Objects().HomCategory(Objects()).parent_class):
pass
....:
---------------------------------------------------------------------------
TypeError Traceback (most recent call
last)
/mnt/local/king/SAGE/sandbox/sage-4.7.2.alpha2/devel/sage-main/<ipython
console> in <module>()
TypeError: Error when calling the metaclass bases
Cannot create a consistent method resolution
order (MRO) for bases Homset, Objects.HomCategory.parent_class
}}}
It seems that the problem is in the order in which the two classes are
presented:
{{{
sage: class Foo(Objects().HomCategory(Objects()).parent_class, Homset):
pass
....:
sage:
}}}
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/10667#comment:16>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/sage-trac?hl=en.
