Add '+' alternatives to signed_number and signed_real_number grammar
rules, mirroring how unary minus is already handled for pattern matching.
Unary plus is a no-op on numbers so the value is returned directly without
wrapping in a UnaryOp node.
* Implement C recursion protection with limit pointers for Linux, MacOS and Windows
* Remove calls to PyOS_CheckStack
* Add stack protection to parser
* Make tests more robust to low stacks
* Improve error messages for stack overflow
Adds a test that length-1 tuple-style sequence patterns must end in a comma, since there isn't currently one.
Spotted while reviewing Cython's proposed implementation of the pattern matching syntax (https://github.com/cython/cython/pull/4897#discussion_r1489177169) where there was a bug my the reimplementation that wasn't caught against the CPython tests here.
The current status quo is that private attribute names are not
mangled when a class is matched. I've added a test to
document/legimize this behaviour.
Co-authored-by: Brandt Bucher <brandtbucher@gmail.com>
