Raise TypeError for bool(Booleans) except true, false

Author: isuruf

symengine/lib/symengine_wrapper.pyx

@@ -1419,6 +1419,9 @@ cdef class Boolean(Expr):
     def logical_not(self):
         return c2py(<rcp_const_basic>(deref(symengine.rcp_static_cast_Boolean(self.thisptr)).logical_not()))
 
+    def __bool__(self):
+        raise TypeError("cannot determine truth value of Boolean")
+
 
 cdef class BooleanAtom(Boolean):
 
@@ -1524,6 +1527,10 @@ class Relational(Boolean):
     def is_Relational(self):
         return True
 
+    def __bool__(self):
+        raise TypeError("cannot determine truth value of Relational")
+
+
 Rel = Relational
 
 

symengine/tests/test_logic.py

@@ -44,6 +44,7 @@ def test_And():
     assert And(True, False) == false
     assert And(False, False) == false
     assert And(True, True, True) == true
+    assert raises(TypeError, lambda: x < y and y < 1)
 
 
 def test_Or():
@@ -54,6 +55,7 @@ def test_Or():
     assert Or(True, False) == true
     assert Or(False, False) == false
     assert Or(True, False, False) == true
+    assert raises(TypeError, lambda: x < y or y < 1)
 
 
 def test_Nor():
@@ -116,4 +118,4 @@ def test_Contains():
     assert Contains(x, Interval(1, 1)) != false
     assert Contains(oo, Interval(-oo, oo)) == false
     assert Contains(-oo, Interval(-oo, oo)) == false
-    
+