There is sage.structure.mutability.Mutability to inherit from. It seems the this class is not used; at least using grep [1] to search for "Mutability" gives just two files (sage/matrix/matrix0.pyx and sage/matrix/matrix_integer_2x2.pyx), where this class is imported. It seems that commenting out the import-lines in those two files does not change anything (no error messages at all; all doctests are still passed). grepping for "structure.mutability", see [2], also does not give anything. So, are there classes, where sage.structure.mutability.Mutability is used?
Further, the code in mutability.pyx seems to be outdated. Comparing the code to the one in sequence.py gives (for example): mutability.pyx:45 self._is_immutable = 1 sequence.py: self._is_immutable = True or a missing "return" in is_immutable. (I noticed those things by just looking at the code in mutability.pyx; probably, comparing those files really would bring more...) Anyhow, a lot of classes implement mutability by themselves, see [3]. Are there already trac-tickets for those things? (if not I'll open some...) The reason, why I looked at this, is, that it was mentioned in a comment on #15078 to use Mutability for the FiniteStateMachine-class. Daniel [1] sage -grep "Mutability" sage/homology/simplicial_complex.py:Mutability (see :trac:`12587`):: sage/matrix/matrix0.pyx:from sage.structure.mutability cimport Mutability sage/matrix/matrix0.pyx: # Mutability and bounds checking sage/matrix/matrix_integer_2x2.pyx:from sage.structure.mutability cimport Mutability sage/structure/mutability.pyx:Mutability Cython Implementation sage/structure/mutability.pyx:cdef class Mutability: sage/structure/mutability.pyx: return Mutability, (self._is_immutable, ) sage/structure/all.py:from mutability import Mutability sage/structure/sequence.py:#from mutability import Mutability #we cannot inherit from Mutability and list at the same time sage/libs/gap/gap_functions.py: 'OneSameMutability', sage/libs/gap/gap_functions.py: 'ZeroSameMutability', [2] sage -grep -i "structure.mutability" sage/matrix/matrix0.pyx:from sage.structure.mutability cimport Mutability sage/matrix/matrix_integer_2x2.pyx:from sage.structure.mutability cimport Mutability sage/structure/mutability.pyx: sage: from sage.structure.mutability import require_mutable, require_immutable sage/structure/mutability.pyx: sage: from sage.structure.mutability import require_mutable, require_immutable [3] sage -grep "def is_immutable" sage/modules/free_module_element.pyx: def is_immutable(self): sage/homology/simplicial_complex.py: def is_immutable(self): sage/matrix/matrix0.pyx: def is_immutable(self): sage/structure/mutability.pyx: def is_immutable(self): sage/structure/sequence.py: def is_immutable(self): sage/libs/ppl.pyx: def is_immutable(self): -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
