WIP - Better comparisons between ExactNumbers

Author: rocky

mathics/builtin/comparison.py

@@ -254,8 +254,12 @@ def do_compare(self, l1, l2) -> Union[bool, None]:
     def apply(self, items, evaluation):
         "%(name)s[items___]"
         items_sequence = items.get_sequence()
-        if len(items_sequence) <= 1:
+        n = len(items_sequence)
+        if n <= 1:
             return SymbolTrue
+        is_exact_vals = [Expression("ExactNumberQ", arg).evaluate(evaluation) for arg in items_sequence]
+        if all(val == SymbolTrue for val in is_exact_vals):
+            return self.apply_other(items, evaluation)
         args = self.numerify_args(items, evaluation)
         wanted = operators[self.get_name()]
         for x, y in itertools.combinations(args, 2):
@@ -274,7 +278,7 @@ def apply(self, items, evaluation):
         return SymbolTrue
 
     def apply_other(self, args, evaluation):
-        "%(name)s[args___?(!RealNumberQ[#]&)]"
+        "%(name)s[args___?(!ExactNumberQ[#]&)]"
         args = args.get_sequence()
         for x, y in itertools.combinations(args, 2):
             c = self.do_compare(x, y)
@@ -285,6 +289,7 @@ def apply_other(self, args, evaluation):
         return SymbolTrue
 
 
+
 class _ComparisonOperator(_InequalityOperator):
     "Compares arguments in a chain e.g. a < b < c compares a < b and b < c."
 

mathics/core/expression.py

@@ -2218,7 +2218,7 @@ def __new__(cls, value) -> 'MachineReal':
     def to_python(self, *args, **kwargs) -> float:
         return self.value
 
-    def to_sympy(self):
+    def to_sympy(self, *args, **kwargs):
         return sympy.Float(self.value)
 
     def to_mpmath(self):

test/test_compare.py

@@ -0,0 +1,23 @@
+# -*- coding: utf-8 -*-
+from .helper import check_evaluation
+
+def test_compare():
+    for str_expr, str_expected in (
+        (
+            "I == I",
+            "True",
+        ),
+        (
+            "I == 0",
+            "False",
+        ),
+        (
+            "I + 0 == 1 I - 0",
+            "True",
+        ),
+        (
+            "I + 5 == I",
+            "False",
+        ),
+    ):
+        check_evaluation(str_expr, str_expected)