On Wed, Oct 31, 2012 at 05:39:06PM -0700, Andrew Mathas wrote:
> I think that the problem is that when sage creates a class then it creates
> copies in memory of all of the (inherited) methods of the class.
Not exactly. What happens is that, for P a parent (here P=Tableaux),
the class P.element_class is not P.Element (here Tableau) but a
subclass of it, constructed to let a tableau inherit code from
categories:
sage: T = Tableaux()
sage: T.Element
<class 'sage.combinat.tableau.Tableau'>
sage: T.element_class
<class 'sage.combinat.tableau.Tableaux_all_with_category.element_class'>
sage: T.element_class.__bases__
(<class 'sage.combinat.tableau.Tableau'>, <class
'sage.categories.sets_cat.Sets.element_class'>)
As a consequence:
sage: issubclass(SemistandardTableaux().element_class,
Tableaux().element_class)
False
even though:
sage: issubclass(SemistandardTableaux().Element, Tableaux().Element)
True
So what you want to do is not to insert your method in the class
of the tableau, but in its superclass (i.e. Tableau):
sage: t = Tableau([[2]])
sage: s = SemistandardTableau([[2]])
sage: t.__class__.__base__.foo = lambda self: 1
sage: t.foo()
1
sage: s.foo()
1
Cheers,
Nicolas
--
Nicolas M. Thiéry "Isil" <nthi...@users.sf.net>
http://Nicolas.Thiery.name/
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