Add OQPyExpression._expr_matches to give subclasses ability to control expr_matches behavior

Author: PhilReinhold

oqpy/base.py

@@ -180,6 +180,12 @@ def __bool__(self) -> bool:
             "the equality of expressions using == instead of expr_matches."
         )
 
+    def _expr_matches(self, other) -> bool:
+        """Called by expr_matches to compare expression instances."""
+        if not isinstance(other, type(self)):
+            return False
+        return expr_matches(self.__dict__, other.__dict__)
+
 
 def _get_type(val: AstConvertible) -> Optional[ast.ClassicalType]:
     if isinstance(val, OQPyExpression):
@@ -332,7 +338,7 @@ def expr_matches(a: Any, b: Any) -> bool:
         return all(expr_matches(va, b[k]) for k, va in a.items())
     if isinstance(a, OQPyExpression):
         # Bypass `__eq__` which is overloaded on OQPyExpressions
-        return expr_matches(a.__dict__, b.__dict__)
+        return a._expr_matches(b)
     else:
         return a == b
 

tests/test_directives.py

@@ -2656,3 +2656,21 @@ class MyFloatVar(oqpy.FloatVar):
     x1 = MyFloatVar(3, name="x")
     x2 = MyFloatVar(3, name="x")
     assert oqpy.base.expr_matches(x1, x2)
+
+    class MyFloatVarWithIgnoredData(oqpy.FloatVar):
+        ignored: int
+        def _expr_matches(self, other):
+            if not isinstance(other, type(self)):
+                return False
+            d1 = self.__dict__.copy()
+            d2 = other.__dict__.copy()
+            d1.pop("ignored")
+            d2.pop("ignored")
+            return oqpy.base.expr_matches(d1, d2)
+
+
+    x1 = MyFloatVarWithIgnoredData(3, name="x")
+    x1.ignored = 1
+    x2 = MyFloatVarWithIgnoredData(3, name="x")
+    x2.ignored = 2
+    assert oqpy.base.expr_matches(x1, x2)