Empty families should be false

[mkoeppe]

sage: Family([])                                                                                                                            
Family ()
sage: bool(_)                                                                                                                               
True

Compare with:

sage: bool(dict())                                                                                                                          
False

CC: @tscrim

Component: combinatorics

Author: Travis Scrimshaw

Branch/Commit: 42abda7

Reviewer: Matthias Koeppe

Issue created by migration from https://trac.sagemath.org/ticket/31717

[tscrim]

comment:1

I added the simple __bool__ check to the appropriate class:

sage: type(Family([]))
<class 'sage.sets.family.TrivialFamily_with_category'>
sage: type(Family({}))
<class 'sage.sets.family.FiniteFamily_with_category'>

---

New commits:

cbbef90

Adding a `__bool__` to trivial family.

[tscrim]

Branch: public/sets/trivial_family_bool-31717

[tscrim]

Commit: cbbef90

[tscrim]

Author: Travis Scrimshaw

[mkoeppe]

comment:2

Shouldn't there also be a change for FiniteFamily?

[sagetrac-git]

Changed commit from cbbef90 to 42abda7

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

42abda7

Adding `__bool__` for other families.

[tscrim]

comment:4

Indeed, there should be. I also added one for LazyFamily.

[mkoeppe]

Reviewer: Matthias Koeppe

[mkoeppe]

comment:5

This works well, thanks a lot

[tscrim]

comment:6

No problem. Thanks for the review.

[vbraun]

Changed branch from public/sets/trivial_family_bool-31717 to 42abda7