| -- Test cases for Python 3.8 features |
| |
| [case testWalrus1] |
| from typing import Optional |
| |
| def foo(x: int) -> Optional[int]: |
| if x < 0: |
| return None |
| return x |
| |
| def test(x: int) -> str: |
| if (n := foo(x)) is not None: |
| return str(x) |
| else: |
| return "<fail>" |
| |
| [file driver.py] |
| from native import test |
| |
| assert test(10) == "10" |
| assert test(-1) == "<fail>" |
| |
| |
| [case testWalrus2] |
| from typing import Optional, Tuple, List |
| |
| class Node: |
| def __init__(self, val: int, next: Optional['Node']) -> None: |
| self.val = val |
| self.next = next |
| |
| def pairs(nobe: Optional[Node]) -> List[Tuple[int, int]]: |
| if nobe is None: |
| return [] |
| l = [] |
| while next := nobe.next: |
| l.append((nobe.val, next.val)) |
| nobe = next |
| return l |
| |
| def make(l: List[int]) -> Optional[Node]: |
| cur: Optional[Node] = None |
| for x in reversed(l): |
| cur = Node(x, cur) |
| return cur |
| |
| [file driver.py] |
| from native import Node, make, pairs |
| |
| assert pairs(make([1,2,3])) == [(1,2), (2,3)] |
| assert pairs(make([1])) == [] |
| assert pairs(make([])) == [] |
