Coverage for local/lib/python2.7/site-packages/sage/structure/mutability.pyx : 39%
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""" Mutability Cython Implementation """
########################################################################## # # Sage: System for Algebra and Geometry Experimentation # # Copyright (C) 2006 William Stein <wstein@gmail.com> # # Distributed under the terms of the GNU General Public License (GPL) # http://www.gnu.org/licenses/ ########################################################################## from __future__ import print_function, absolute_import
cdef class Mutability:
def __init__(self, is_immutable=False): self._is_immutable = is_immutable
def _require_mutable(self): if self._is_immutable: raise ValueError("object is immutable; please change a copy instead.")
cdef _require_mutable_cdef(self): if self._is_immutable: raise ValueError("object is immutable; please change a copy instead.")
def set_immutable(self): """ Make this object immutable, so it can never again be changed.
EXAMPLES::
sage: v = Sequence([1,2,3,4/5]) sage: v[0] = 5 sage: v [5, 2, 3, 4/5] sage: v.set_immutable() sage: v[3] = 7 Traceback (most recent call last): ... ValueError: object is immutable; please change a copy instead. """ self._is_immutable = 1
def is_immutable(self): """ Return True if this object is immutable (can not be changed) and False if it is not.
To make this object immutable use self.set_immutable().
EXAMPLES::
sage: v = Sequence([1,2,3,4/5]) sage: v[0] = 5 sage: v [5, 2, 3, 4/5] sage: v.is_immutable() False sage: v.set_immutable() sage: v.is_immutable() True """ self._is_immutable
def is_mutable(self): return not self._is_immutable
def __reduce__(self): return Mutability, (self._is_immutable, )
################################################################################# ## Method decorators for mutating methods resp. methods that assume immutability from sage.misc.decorators import sage_wraps
def require_mutable(f): """ A decorator that requires mutability for a method to be called.
EXAMPLES::
sage: from sage.structure.mutability import require_mutable, require_immutable sage: class A(object): ....: def __init__(self, val): ....: self._m = val ....: @require_mutable ....: def change(self, new_val): ....: 'change self' ....: self._m = new_val ....: @require_immutable ....: def __hash__(self): ....: 'implement hash' ....: return hash(self._m) sage: a = A(5) sage: a.change(6) sage: hash(a) Traceback (most recent call last): ... ValueError: <class '__main__.A'> instance is mutable, <function __hash__ at ...> must not be called sage: a._is_immutable = True sage: hash(a) 6 sage: a.change(7) # indirect doctest Traceback (most recent call last): ... ValueError: <class '__main__.A'> instance is immutable, <function change at ...> must not be called sage: from sage.misc.sageinspect import sage_getdoc sage: print(sage_getdoc(a.change)) change self
AUTHORS:
- Simon King <simon.king@uni-jena.de> """
def require_immutable(f): """ A decorator that requires mutability for a method to be called.
EXAMPLES::
sage: from sage.structure.mutability import require_mutable, require_immutable sage: class A(object): ....: def __init__(self, val): ....: self._m = val ....: @require_mutable ....: def change(self, new_val): ....: 'change self' ....: self._m = new_val ....: @require_immutable ....: def __hash__(self): ....: 'implement hash' ....: return hash(self._m) sage: a = A(5) sage: a.change(6) sage: hash(a) # indirect doctest Traceback (most recent call last): ... ValueError: <class '__main__.A'> instance is mutable, <function __hash__ at ...> must not be called sage: a._is_immutable = True sage: hash(a) 6 sage: a.change(7) Traceback (most recent call last): ... ValueError: <class '__main__.A'> instance is immutable, <function change at ...> must not be called sage: from sage.misc.sageinspect import sage_getdoc sage: print(sage_getdoc(a.__hash__)) implement hash
AUTHORS:
- Simon King <simon.king@uni-jena.de> """ |