Features for testing the presence of bliss

class sage.features.bliss.Bliss(*args, **kwds)

Bases: BuildModule

A Feature which describes whether the sage.graphs.bliss module is available in this installation of Sage.

EXAMPLES:

Sage

sage: from sage.features.bliss import Bliss
sage: Bliss().is_present()  # needs bliss
FeatureTestResult('bliss', True)
sage: Bliss().is_present()  # needs !bliss
FeatureTestResult('bliss', False)

Python

>>> from sage.all import *
>>> from sage.features.bliss import Bliss
>>> Bliss().is_present()  # needs bliss
FeatureTestResult('bliss', True)
>>> Bliss().is_present()  # needs !bliss
FeatureTestResult('bliss', False)

Sage Live

from sage.features.bliss import Bliss
Bliss().is_present()  # needs bliss
Bliss().is_present()  # needs !bliss

A runtime check. We only check the “present” case because, if feature checks are _not_ deferred, the needs !bliss can be satisfied (disabled at build time) at the same time we are able to import a module that was installed for a previous build of sage:

Sage

sage: from sage.features.bliss import Bliss
sage: Bliss().is_present_at_runtime()  # needs bliss
FeatureTestResult('bliss', True)

Python

>>> from sage.all import *
>>> from sage.features.bliss import Bliss
>>> Bliss().is_present_at_runtime()  # needs bliss
FeatureTestResult('bliss', True)

Sage Live

from sage.features.bliss import Bliss
Bliss().is_present_at_runtime()  # needs bliss

sage.features.bliss.all_features()

Make live