sage -> pyeantic conversion failure

[videlec]

When the sage number field does not use x for the variable name of the defining polynomial pyeantic got confused

sage: from pyeantic import RealEmbeddedNumberField
sage: y = polygen(QQ, 'y')
sage: K = NumberField(y**2 - 2, 'b', embedding=sqrt(AA(2)))
sage: KK = RealEmbeddedNumberField(K)
sage: KK(K.gen())
Traceback (most recent call last):
<ipython-input-78-742a653cb9b8> in <module>
      2 K = NumberField(y**Integer(2) - Integer(2), 'b', embedding=sqrt(AA(Integer(2))))
      3 KK = RealEmbeddedNumberField(K)
----> 4 KK(K.gen())

~/miniconda3/envs/flatsurf/lib/python3.9/site-packages/sage/structure/parent.pyx in sage.structure.parent.Parent.__call__ (build/cythonized/sage/structure/parent.c:9335)()
    898         if mor is not None:
    899             if no_extra_args:
--> 900                 return mor._call_(x)
    901             else:
    902                 return mor._call_with_args(x, args, kwds)

~/miniconda3/envs/flatsurf/lib/python3.9/site-packages/sage/categories/map.pyx in sage.categories.map.FormalCompositeMap._call_ (build/cythonized/sage/categories/map.c:11818)()
   1692         """
   1693         for f in self.__list:
-> 1694             x = f._call_(x)
   1695         return x
   1696 

~/miniconda3/envs/flatsurf/lib/python3.9/site-packages/pyeantic/real_embedded_number_field.py in _call_(self, x)
    665             b
    666         """
--> 667         rational_coefficients = [ZZ(str(c.get_str())) / ZZ(str(x.renf_elem.den().get_str())) for c in x.renf_elem.num_vector()]
    668         while len(rational_coefficients) < self.domain().number_field.degree():
    669             rational_coefficients.append(QQ.zero())

~/miniconda3/envs/flatsurf/lib/python3.9/site-packages/sage/structure/element.pyx in sage.structure.element.Element.__getattr__ (build/cythonized/sage/structure/element.c:4701)()
    491             AttributeError: 'LeftZeroSemigroup_with_category.element_class' object has no attribute 'blah_blah'
    492         """
--> 493         return self.getattr_from_category(name)
    494 
    495     cdef getattr_from_category(self, name):

~/miniconda3/envs/flatsurf/lib/python3.9/site-packages/sage/structure/element.pyx in sage.structure.element.Element.getattr_from_category (build/cythonized/sage/structure/element.c:4813)()
    504         else:
    505             cls = P._abstract_element_class
--> 506         return getattr_from_other_class(self, cls, name)
    507 
    508     def __dir__(self):

~/miniconda3/envs/flatsurf/lib/python3.9/site-packages/sage/cpython/getattr.pyx in sage.cpython.getattr.getattr_from_other_class (build/cythonized/sage/cpython/getattr.c:2619)()
    370         dummy_error_message.cls = type(self)
    371         dummy_error_message.name = name
--> 372         raise AttributeError(dummy_error_message)
    373     attribute = <object>attr
    374     # Check for a descriptor (__get__ in Python)

AttributeError: 'sage.rings.number_field.number_field_element_quadratic.NumberFieldElement_quadratic' object has no attribute 'renf_elem'

[saraedum]

What's really odd here is that KK(K.gen()) calls a coercion from KK into K (!)

Unsurprisingly, that coercion then fails because the element is not actually in KK but in K.

[saraedum]

Fixed in #196.