Let categories override the default implementation of __getitem__ in Parent

[nthiery]

Parent.getitem should be moved to FiniteEnumeratedSets (#12955). Alas, this is not yet possible since too many finite enumerated sets in Sage are not in the FiniteEnumeratedSets category (see #12957). In the meantime, this patch provides a workaround by asking Parent.getitem to first try to call __getitem__ on its super classes.

CC: @sagetrac-sage-combinat

Component: categories

Keywords: getitem

Author: Nicolas M. Thiéry

Reviewer: Franco Saliola

Merged: sage-5.1.beta1

Issue created by migration from https://trac.sagemath.org/ticket/12956

[nthiery]

Description changed:

--- 
+++ 
@@ -1 +1 @@
-Parent.__getitem__ should be moved to FiniteEnumeratedSets (#12955). Alas, this is not yet possible since too many finite enumerated sets in Sage are not in the FiniteEnumeratedSets category. In the meantime, this patch provides a workaround by asking Parent.__getitem__ to first try to call `__getitem__` on its super class.
+Parent.__getitem__ should be moved to FiniteEnumeratedSets (#12955). Alas, this is not yet possible since too many finite enumerated sets in Sage are not in the FiniteEnumeratedSets category (see #12957). In the meantime, this patch provides a workaround by asking Parent.__getitem__ to first try to call `__getitem__` on its super classes.

[nthiery]

Attachment: trac_12956-parent_categories_getitem-nt.patch.gz

[nthiery]

Changed keywords from none to getitem

[nthiery]

Reviewer: Franco Saliola

[nthiery]

comment:3

All tests pass on 5.0 + above patches with positive review in the Sage-Combinat queue.

Positive review on behalf of Franco sitting next to me.

[jdemeyer]

Merged: sage-5.1.beta1