feat(insights): Support unary minus and plus in formulas (#23119)

* feat(insights): Support unary minus and plus in formulas

* Fix variable use issue

posthog/hogql_queries/utils/formula_ast.py

@@ -49,14 +49,22 @@ def _evaluate(self, node, const_map: dict[str, Any]):
             left = self._evaluate(node.left, const_map)
             op = node.op
             right = self._evaluate(node.right, const_map)
-
             try:
                 return self.op_map[type(op)](left, right)
             except ZeroDivisionError:
                 return 0
             except KeyError:
                 raise ValueError(f"Operator {op.__class__.__name__} not supported")
 
+        elif isinstance(node, ast.UnaryOp):
+            operand = self._evaluate(node.operand, const_map)
+            unary_op = node.op
+            if isinstance(unary_op, ast.USub):
+                return -operand
+            elif isinstance(unary_op, ast.UAdd):
+                return operand
+            raise ValueError(f"Operator {unary_op.__class__.__name__} not supported")
+
         elif isinstance(node, ast.Num):
             return node.n
 

posthog/hogql_queries/utils/test/test_formula_ast.py

@@ -56,3 +56,13 @@ def test_named_values_lower_case(self):
         formula = self._get_formula_ast()
         response = formula.call("a+b")
         self.assertListEqual([2, 4, 6, 8], response)
+
+    def test_unary_minus(self):
+        formula = self._get_formula_ast()
+        response = formula.call("-A")
+        self.assertListEqual([-1, -2, -3, -4], response)
+
+    def test_unary_plus(self):
+        formula = self._get_formula_ast()
+        response = formula.call("+A")
+        self.assertListEqual([1, 2, 3, 4], response)