Use 3.10 with cython

3.11 seems to use to require more stringent cython.

While this is a good thing. Right now we should focus on one issue at a
time.

The issue here is TOM, not 3.11 Cython stringencies

.github/workflows/ubuntu-cython.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        python-version: ['3.11']
+        python-version: ['3.10']
     steps:
     - uses: actions/checkout@v3
     - name: Set up Python ${{ matrix.python-version }}

mathics/core/atoms.py

@@ -545,9 +545,9 @@ def __neg__(self) -> "PrecisionReal":
     def do_copy(self) -> "PrecisionReal":
         return PrecisionReal(self.value)
 
-    def get_precision(self) -> float:
+    def get_precision(self) -> int:
         """Returns the default specification for precision (in binary digits) in N and other numerical functions."""
-        return self.value._prec + 1.0
+        return self.value._prec + 1
 
     @property
     def is_zero(self) -> bool:
@@ -801,6 +801,7 @@ def is_machine_precision(self) -> bool:
             return True
         return False
 
+    # FIXME: funny name get_float_value returns complex?
     def get_float_value(self, permit_complex=False) -> Optional[complex]:
         if permit_complex:
             real = self.real.get_float_value()
@@ -810,7 +811,7 @@ def get_float_value(self, permit_complex=False) -> Optional[complex]:
         else:
             return None
 
-    def get_precision(self) -> Optional[float]:
+    def get_precision(self) -> Optional[int]:
         """Returns the default specification for precision in N and other numerical functions.
         When `None` is be returned no precision is has been defined and this object's value is
         exact.

mathics/core/number.py

@@ -70,7 +70,7 @@ def _get_float_inf(value, evaluation) -> Optional[float]:
 
 def get_precision(
     value: BaseElement, evaluation, show_messages: bool = True
-) -> Optional[float]:
+) -> Optional[int]:
     """
     Returns the ``float`` in the interval [``$MinPrecision``, ``$MaxPrecision``] closest
     to ``value``.

mathics/core/symbols.py

@@ -2,7 +2,7 @@
 # -*- coding: utf-8 -*-
 
 import time
-from typing import Any, FrozenSet, List, Optional
+from typing import Any, FrozenSet, List, Optional, Union
 
 from mathics.core.element import (
     BaseElement,
@@ -830,7 +830,11 @@ def __floordiv__(self, other) -> BaseElement:
     def __pow__(self, other) -> BaseElement:
         return self.create_expression(SymbolPower, self, other)
 
-    def round_to_float(self, evaluation=None, permit_complex=False) -> Optional[float]:
+    # FIXME: The name "round_to_float" is misleading when
+    # permit_complex is True.
+    def round_to_float(
+        self, evaluation=None, permit_complex=False
+    ) -> Optional[Union[complex | float]]:
         """
         Round to a Python float. Return None if rounding is not possible.
         This can happen if self or evaluation is NaN.