def encapsulate()

in bowler/query.py [0:0]


    def encapsulate(self, internal_name: str = "") -> "Query":
        transform = self.current
        if transform.selector not in ("attribute"):
            raise ValueError("encapsulate requires select_attribute")

        if not any("filter_in_class" in f.__name__ for f in transform.filters):
            raise ValueError("encapsulate requires in_class filter")

        make_property = Once()
        old_name = transform.kwargs["name"]
        new_name = internal_name or f"_{old_name}"

        if new_name.startswith("__"):
            raise ValueError(
                "renaming {old_name} -> {new_name} is dangerous, "
                "please specify internal_name to avoid name mangling"
            )

        def encapsulate_transform(
            node: LN, capture: Capture, filename: Filename
        ) -> None:
            if "attr_assignment" in capture:
                leaf = capture["attr_name"]
                leaf.replace(Name(new_name, prefix=leaf.prefix))

                if make_property:
                    # TODO: capture and use type annotation from original assignment

                    class_node = get_class(node)
                    suite = find_first(class_node, SYMBOL.suite)
                    assert isinstance(suite, Node)
                    indent_node = find_first(suite, TOKEN.INDENT)
                    assert isinstance(indent_node, Leaf)
                    indent = indent_node.value

                    getter = Node(
                        SYMBOL.decorated,
                        [
                            Node(
                                SYMBOL.decorator,
                                [
                                    Leaf(TOKEN.INDENT, indent),
                                    Leaf(TOKEN.AT, "@"),
                                    Name("property"),
                                    Leaf(TOKEN.NEWLINE, "\n"),
                                ],
                            ),
                            Node(
                                SYMBOL.funcdef,
                                [
                                    Name("def", indent),
                                    Name(old_name, prefix=" "),
                                    Node(
                                        SYMBOL.parameters,
                                        [LParen(), Name("self"), RParen()],
                                    ),
                                    Leaf(TOKEN.COLON, ":"),
                                    Node(
                                        SYMBOL.suite,
                                        [
                                            Newline(),
                                            Leaf(TOKEN.INDENT, indent + "    "),
                                            Node(
                                                SYMBOL.simple_stmt,
                                                [
                                                    Node(
                                                        SYMBOL.return_stmt,
                                                        [
                                                            Name("return"),
                                                            Node(
                                                                SYMBOL.power,
                                                                Attr(
                                                                    Name("self"),
                                                                    Name(new_name),
                                                                ),
                                                                prefix=" ",
                                                            ),
                                                        ],
                                                    ),
                                                    Newline(),
                                                ],
                                            ),
                                            Leaf(TOKEN.DEDENT, "\n" + indent),
                                        ],
                                    ),
                                ],
                                prefix=indent,
                            ),
                        ],
                    )

                    setter = Node(
                        SYMBOL.decorated,
                        [
                            Node(
                                SYMBOL.decorator,
                                [
                                    Leaf(TOKEN.AT, "@"),
                                    Node(
                                        SYMBOL.dotted_name,
                                        [Name(old_name), Dot(), Name("setter")],
                                    ),
                                    Leaf(TOKEN.NEWLINE, "\n"),
                                ],
                            ),
                            Node(
                                SYMBOL.funcdef,
                                [
                                    Name("def", indent),
                                    Name(old_name, prefix=" "),
                                    Node(
                                        SYMBOL.parameters,
                                        [
                                            LParen(),
                                            Node(
                                                SYMBOL.typedargslist,
                                                [
                                                    Name("self"),
                                                    Comma(),
                                                    Name("value", prefix=" "),
                                                ],
                                            ),
                                            RParen(),
                                        ],
                                    ),
                                    Leaf(TOKEN.COLON, ":"),
                                    Node(
                                        SYMBOL.suite,
                                        [
                                            Newline(),
                                            Leaf(TOKEN.INDENT, indent + "    "),
                                            Node(
                                                SYMBOL.simple_stmt,
                                                [
                                                    Node(
                                                        SYMBOL.expr_stmt,
                                                        [
                                                            Node(
                                                                SYMBOL.power,
                                                                Attr(
                                                                    Name("self"),
                                                                    Name(new_name),
                                                                ),
                                                            ),
                                                            Leaf(
                                                                TOKEN.EQUAL,
                                                                "=",
                                                                prefix=" ",
                                                            ),
                                                            Name("value", prefix=" "),
                                                        ],
                                                    ),
                                                    Newline(),
                                                ],
                                            ),
                                            Leaf(TOKEN.DEDENT, "\n" + indent),
                                        ],
                                    ),
                                ],
                                prefix=indent,
                            ),
                        ],
                    )

                    suite.insert_child(-1, getter)
                    suite.insert_child(-1, setter)

                    prev = find_previous(getter, TOKEN.DEDENT, recursive=True)
                    curr = find_last(setter, TOKEN.DEDENT, recursive=True)
                    if prev and curr:
                        assert isinstance(prev, Leaf) and isinstance(curr, Leaf)
                        prev.prefix, curr.prefix = curr.prefix, prev.prefix
                        prev.value, curr.value = curr.value, prev.value

        transform.callbacks.append(encapsulate_transform)
        return self