Trac #21887: py3 making __nonzero__ an alias for __bool__ in rings fo…

…lder

as a step to py3

part of #16076

here only in the rings folder

URL: https://trac.sagemath.org/21887
Reported by: chapoton
Ticket author(s): Frédéric Chapoton
Reviewer(s): Jeroen Demeyer

src/sage/rings/asymptotic/asymptotic_ring.py

@@ -779,7 +779,7 @@ def __hash__(self):
         return hash(str(self))
 
 
-    def __nonzero__(self):
+    def __bool__(self):
         r"""
         Return whether this asymptotic expansion is not identically zero.
 
@@ -803,6 +803,7 @@ def __nonzero__(self):
         """
         return bool(self._summands_)
 
+    __nonzero__ = __bool__
 
     def __eq__(self, other):
         r"""

src/sage/rings/complex_interval.pyx

@@ -1395,20 +1395,18 @@ cdef class ComplexIntervalFieldElement(sage.structure.element.FieldElement):
 
         EXAMPLES::
 
-            sage: CIF(RIF(0, 0), RIF(0, 0)).__nonzero__()
-            False
             sage: bool(CIF(RIF(0, 0), RIF(0, 0)))
             False
-            sage: CIF(RIF(1), RIF(0)).__nonzero__()
+            sage: bool(CIF(RIF(1), RIF(0)))
             True
-            sage: CIF(RIF(0), RIF(1)).__nonzero__()
+            sage: bool(CIF(RIF(0), RIF(1)))
             True
-            sage: CIF(RIF(1, 2), RIF(0)).__nonzero__()
+            sage: bool(CIF(RIF(1, 2), RIF(0)))
             True
-            sage: CIF(RIF(-1, 1), RIF(-1, 1)).__nonzero__()
+            sage: bool(CIF(RIF(-1, 1), RIF(-1, 1)))
             True
         """
-        return self.real().__nonzero__() or self.imag().__nonzero__()
+        return bool(self.real()) or bool(self.imag())
 
     cpdef _richcmp_(left, right, int op):
         r"""

src/sage/rings/continued_fraction.py

@@ -986,7 +986,7 @@ def ceil(self):
             return self.quotient(0)
         return self.quotient(0)+1
 
-    def __nonzero__(self):
+    def __bool__(self):
         """
         Return False if self is zero.
 
@@ -1003,6 +1003,8 @@ def __nonzero__(self):
         """
         return bool(self.quotient(0)) or self.quotient(1) is not Infinity
 
+    __nonzero__ = __bool__
+
     def is_zero(self):
         r"""
         Test whether ``self`` is zero.

src/sage/rings/fraction_field_element.pyx

@@ -878,12 +878,12 @@ cdef class FractionFieldElement(FieldElement):
             sage: F = ZZ['x,y'].fraction_field()
             sage: x,y = F.gens()
             sage: t = F(0)/x
-            sage: t.__nonzero__()
+            sage: bool(t)
             False
 
         ::
 
-            sage: (1/x).__nonzero__()
+            sage: bool(1/x)
             True
         """
         return not self.__numerator.is_zero()

src/sage/rings/ideal.py

@@ -386,7 +386,7 @@ def _contains_(self, x):
         """
         raise NotImplementedError
 
-    def __nonzero__(self):
+    def __bool__(self):
         r"""
         Return ``True`` if this ideal is not `(0)`.
 
@@ -419,6 +419,8 @@ def __nonzero__(self):
                 return True
         return False
 
+    __nonzero__ = __bool__
+
     def base_ring(self):
         r"""
         Returns the base ring of this ideal.

src/sage/rings/multi_power_series_ring_element.py

@@ -220,7 +220,7 @@ class MPowerSeries(PowerSeries):
     #
     # _mul_prec : works just fine
     #
-    # __nonzero__ : works just fine
+    # __bool__ : works just fine
     #
     """
     Multivariate power series; these are the elements of Multivariate Power

src/sage/rings/number_field/number_field_element.pyx

@@ -2272,17 +2272,15 @@ cdef class NumberFieldElement(FieldElement):
         EXAMPLES::
 
             sage: m.<b> = CyclotomicField(17)
-            sage: m(0).__nonzero__()
+            sage: bool(m(0))
             False
-            sage: b.__nonzero__()
+            sage: bool(b)
             True
 
-        Nonzero is used by the bool command::
+        ``__bool__`` is used by the bool command::
 
             sage: bool(b + 1)
             True
-            sage: bool(m(0))
-            False
         """
         return not IsZero_ZZX(self.__numerator)
 

src/sage/rings/polynomial/multi_polynomial_element.py

@@ -1464,7 +1464,7 @@ def __ne__(self,right):
             return CommutativeRingElement.__ne__(self, right)
         return self._MPolynomial_element__element != right._MPolynomial_element__element
 
-    def __nonzero__(self):
+    def __bool__(self):
         """
         Returns True if self != 0
 
@@ -1474,6 +1474,8 @@ def __nonzero__(self):
         """
         return self._MPolynomial_element__element.dict()!={}
 
+    __nonzero__ = __bool__
+
     def _floordiv_(self, right):
         r"""
         Quotient of division of self by other. This is denoted //.

src/sage/rings/polynomial/polynomial_element.pyx

@@ -8986,8 +8986,9 @@ cdef class Polynomial_generic_dense(Polynomial):
         Check that exceptions are propagated correctly (:trac:`18274`)::
 
             sage: class BrokenRational(Rational):
-            ....:     def __nonzero__(self):
+            ....:     def __bool__(self):
             ....:         raise NotImplementedError("cannot check whether number is non-zero")
+            ....:     __nonzero__ = __bool__
             sage: z = BrokenRational()
             sage: R.<x> = QQ[]
             sage: from sage.rings.polynomial.polynomial_element import Polynomial_generic_dense

src/sage/rings/polynomial/polynomial_integer_dense_flint.pyx

@@ -756,11 +756,11 @@ cdef class Polynomial_integer_dense_flint(Polynomial):
         EXAMPLES::
 
             sage: R.<x> = ZZ[]
-            sage: R(0).__nonzero__()
+            sage: bool(R(0))
             False
-            sage: R(1).__nonzero__()
+            sage: bool(R(1))
             True
-            sage: x.__nonzero__()
+            sage: bool(x)
             True
         """
         return not (fmpz_poly_degree(self.__poly) == -1)

src/sage/rings/polynomial/skew_polynomial_element.pyx

@@ -1685,10 +1685,10 @@ cdef class SkewPolynomial(AlgebraElement):
             sage: sigma = R.hom([t+1])
             sage: S.<x> = R['x',sigma]
             sage: a = x + 1
-            sage: a.__nonzero__()
+            sage: bool(a)
             True
             sage: b = S.zero()
-            sage: b.__nonzero__()
+            sage: bool(b)
             False
         """
         return not self.is_zero()

src/sage/rings/power_series_poly.pyx

@@ -147,11 +147,11 @@ cdef class PowerSeries_poly(PowerSeries):
         EXAMPLES::
 
             sage: R.<t> = GF(11)[[]]
-            sage: (1 + t + O(t^18)).__nonzero__()
+            sage: bool(1 + t + O(t^18))
             True
-            sage: R(0).__nonzero__()
+            sage: bool(R(0))
             False
-            sage: O(t^18).__nonzero__()
+            sage: bool(O(t^18))
             False
         """
         return not not self.__f

src/sage/rings/qqbar.py

@@ -3805,17 +3805,17 @@ def __ne__(self, other):
         """
         return not self == other
 
-    def __nonzero__(self):
+    def __bool__(self):
         """
         Check whether self is equal is nonzero. This is fast if
         interval arithmetic proves that self is nonzero, but may be
         slow if the number actually is very close to zero.
 
         EXAMPLES::
 
-            sage: (QQbar.zeta(2) + 1).__nonzero__()
+            sage: bool(QQbar.zeta(2) + 1)
             False
-            sage: (QQbar.zeta(7) / (2^500)).__nonzero__()
+            sage: bool(QQbar.zeta(7) / (2^500))
             True
         """
         val = self._value
@@ -3832,7 +3832,9 @@ def __nonzero__(self):
 
         # Sigh...
         self.exactify()
-        return self.__nonzero__()
+        return self.__bool__()
+
+    __nonzero__ = __bool__
 
     def __pow__(self, e):
         r""" ``self**p`` returns the `p`'th power of self (where `p` can

src/sage/rings/quotient_ring_element.py

@@ -126,7 +126,7 @@ def lift(self):
         """
         return self.__rep
 
-    def __nonzero__(self):
+    def __bool__(self):
         """
         Return True if quotient ring element is non-zero in the
         quotient ring `R/I`, by determining whether the element
@@ -143,13 +143,13 @@ def __nonzero__(self):
 
         TESTS::
 
-            sage: S(0).__nonzero__()
-            False
-            sage: (a-a).__nonzero__()
+            sage: bool(a - a)
             False
         """
         return self.__rep not in self.parent().defining_ideal()
 
+    __nonzero__ = __bool__
+
     def is_unit(self):
         """
         Return True if self is a unit in the quotient ring.

src/sage/rings/rational.pyx

@@ -2559,9 +2559,7 @@ cdef class Rational(sage.structure.element.FieldElement):
 
         EXAMPLES::
 
-            sage: (-4/17).__nonzero__()
-            True
-            sage: (0/5).__nonzero__()
+            sage: bool(0/5)
             False
             sage: bool(-4/17)
             True

src/sage/rings/real_mpfi.pyx

@@ -3737,15 +3737,15 @@ cdef class RealIntervalFieldElement(RingElement):
 
         EXAMPLES::
 
-            sage: RIF(0).__nonzero__()
+            sage: bool(RIF(0))
             False
-            sage: RIF(1).__nonzero__()
+            sage: bool(RIF(1))
             True
-            sage: RIF(1, 2).__nonzero__()
+            sage: bool(RIF(1, 2))
             True
-            sage: RIF(0, 1).__nonzero__()
+            sage: bool(RIF(0, 1))
             True
-            sage: RIF(-1, 1).__nonzero__()
+            sage: bool(RIF(-1, 1))
             True
         """
         return not (mpfr_zero_p(&self.value.left) and mpfr_zero_p(&self.value.right))

src/sage/rings/real_mpfr.pyx

@@ -3790,18 +3790,18 @@ cdef class RealNumber(sage.structure.element.RingElement):
 
         EXAMPLES::
 
-            sage: RR(1).__nonzero__()
+            sage: bool(RR(1))
             True
-            sage: RR(0).__nonzero__()
+            sage: bool(RR(0))
             False
-            sage: RR('inf').__nonzero__()
+            sage: bool(RR('inf'))
             True
 
         TESTS:
 
         Check that :trac:`20502` is fixed::
 
-            sage: RR('nan').__nonzero__()
+            sage: bool(RR('nan'))
             True
             sage: RR('nan').is_zero()
             False

src/sage/rings/universal_cyclotomic_field.py

@@ -275,7 +275,7 @@ def __init__(self, parent, obj):
         self._obj = obj
         FieldElement.__init__(self, parent)
 
-    def __nonzero__(self):
+    def __bool__(self):
         r"""
         TESTS::
 
@@ -285,6 +285,8 @@ def __nonzero__(self):
         """
         return bool(self._obj)
 
+    __nonzero__ = __bool__
+
     def __reduce__(self):
         r"""
         TESTS::