From bc95973b51abadc84960e7836ce313f12cf515cf Mon Sep 17 00:00:00 2001 From: Raymond Hettinger Date: Fri, 8 Oct 2010 00:47:45 +0000 Subject: Fix handling on negative numbers in ast.literal_eval(). --- Lib/ast.py | 20 +++++++++++++------- Lib/test/test_ast.py | 4 +++- Misc/NEWS | 4 ++++ 3 files changed, 20 insertions(+), 8 deletions(-) diff --git a/Lib/ast.py b/Lib/ast.py index aab61d7..4b2063b 100644 --- a/Lib/ast.py +++ b/Lib/ast.py @@ -65,19 +65,25 @@ def literal_eval(node_or_string): elif isinstance(node, Name): if node.id in _safe_names: return _safe_names[node.id] + elif isinstance(node, UnaryOp) and \ + isinstance(node.op, (UAdd, USub)) and \ + isinstance(node.operand, (Num, UnaryOp, BinOp)): + operand = _convert(node.operand) + if isinstance(node.op, UAdd): + return + operand + else: + return - operand elif isinstance(node, BinOp) and \ isinstance(node.op, (Add, Sub)) and \ - isinstance(node.right, Num) and \ - isinstance(node.right.n, complex) and \ - isinstance(node.left, Num) and \ - isinstance(node.left.n, (int, float)): - left = node.left.n - right = node.right.n + isinstance(node.right, (Num, UnaryOp, BinOp)) and \ + isinstance(node.left, (Num, UnaryOp, BinOp)): + left = _convert(node.left) + right = _convert(node.right) if isinstance(node.op, Add): return left + right else: return left - right - raise ValueError('malformed string') + raise ValueError('malformed node or string: ' + repr(node)) return _convert(node_or_string) diff --git a/Lib/test/test_ast.py b/Lib/test/test_ast.py index f00a415..b5295ef 100644 --- a/Lib/test/test_ast.py +++ b/Lib/test/test_ast.py @@ -288,12 +288,14 @@ class ASTHelpers_Test(unittest.TestCase): self.assertEqual(ast.literal_eval('{1, 2, 3}'), {1, 2, 3}) self.assertEqual(ast.literal_eval('b"hi"'), b"hi") self.assertRaises(ValueError, ast.literal_eval, 'foo()') + self.assertEqual(ast.literal_eval('-6'), -6) + self.assertEqual(ast.literal_eval('-6j+3'), 3-6j) + self.assertEqual(ast.literal_eval('3.25'), 3.25) def test_literal_eval_issue4907(self): self.assertEqual(ast.literal_eval('2j'), 2j) self.assertEqual(ast.literal_eval('10 + 2j'), 10 + 2j) self.assertEqual(ast.literal_eval('1.5 - 2j'), 1.5 - 2j) - self.assertRaises(ValueError, ast.literal_eval, '2 + (3 + 4j)') def test_main(): diff --git a/Misc/NEWS b/Misc/NEWS index e62dc77..ade83bf 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -10,6 +10,10 @@ What's New in Python 3.2 Alpha 3? Core and Builtins ----------------- +- ast.literal_eval() can now handle negative numbers. It is also a little + more liberal in what it accepts without compromising the safety of the + evaluation. For example, 3j+4 and 3+4+5 are both accepted. + - Issue #10006: type.__abstractmethods__ now raises an AttributeError. As a result metaclasses can now be ABCs (see #9533). -- cgit v0.12