Fix deleting a value from a map.

[jacqueswww]

What's your issue about?

It seems that del keyword doesn't work for a map.

E           vyper.exceptions.StructureException: line 14: Unsupported statement type
E               del self.big_storage[key]
E           ----^

Example test case:

def test_map_delete(get_contract):
    code = """
big_storage: bytes32[bytes32]

@public
def set(key: bytes32, value: bytes32):
    self.big_storage[key] = value

@public
def get(key: bytes32) -> bytes32:
    return self.big_storage[key]

@public
def delete(key: bytes32):
    del self.big_storage[key]
    """

    c = get_contract(code)

    assert c.get("test") == b""
    assert c.set("test", "value")
    assert c.get("test") == b"value"
    c.delete("test")
    assert c.get("test") == b""

This will be done

How can it be fixed?

Fixed by using SSTORE 0x0on the sha32'ed key value.

Cute Animal Picture

[fubuloubu]

I think this is actually good syntax for those coming from Python 👍