How to use the stone.ir.StructField function in stone

def _make_namespace_with_many_structs():
    # type: (...) -> ApiNamespace
    ns = ApiNamespace('ns_with_many_structs')

    struct1 = Struct(name='Struct1', namespace=ns, ast_node=None)
    struct1.set_attributes(None, [StructField('f1', Boolean(), None, None)])
    ns.add_data_type(struct1)

    struct2 = Struct(name='Struct2', namespace=ns, ast_node=None)
    struct2.set_attributes(
        doc=None,
        fields=[
            StructField('f2', List(UInt64()), None, None),
            StructField('f3', Timestamp(ISO_8601_FORMAT), None, None),
            StructField('f4', Map(String(), UInt64()), None, None)
        ]
    )
    ns.add_data_type(struct2)

    return ns

def test_struct_with_custom_annotations(self):
        # type: () -> None
        ns = ApiNamespace('files')
        annotation_type = AnnotationType('MyAnnotationType', ns, None, [
            AnnotationTypeParam('test_param', Int32(), None, False, None, None)
        ])
        ns.add_annotation_type(annotation_type)
        annotation = CustomAnnotation('MyAnnotation', ns, None, 'MyAnnotationType',
            None, [], {'test_param': 42})
        annotation.set_attributes(annotation_type)
        ns.add_annotation(annotation)
        struct = Struct('MyStruct', ns, None)
        struct.set_attributes(None, [
            StructField('annotated_field', Int32(), None, None),
            StructField('unannotated_field', Int32(), None, None),
        ])
        struct.fields[0].set_annotations([annotation])

        result = self._evaluate_struct(ns, struct)

        expected = textwrap.dedent('''\
            class MyStruct(bb.Struct):

                __slots__ = [
                    '_annotated_field_value',
                    '_annotated_field_present',
                    '_unannotated_field_value',
                    '_unannotated_field_present',
                ]

shared_folder_id = Alias('SharedFolderId', ns, None)
        shared_folder_id.set_attributes(None, namespace_id)
        path_root_id = Alias('PathRootId', ns, None)
        path_root_id.set_attributes(None, shared_folder_id)
        nullable_alias = Alias('NullableAlias', ns, None)
        nullable_alias.set_attributes(None, Nullable(path_root_id))

        ns.add_alias(namespace_id)
        ns.add_alias(shared_folder_id)
        ns.add_alias(path_root_id)
        ns.add_alias(nullable_alias)

        test_struct = Struct('TestStruct', ns, None)
        test_struct.set_attributes(None, [
            StructField('field_alias', path_root_id, None, None),
            StructField('field_nullable_alias', nullable_alias, None, None),
            StructField('field_list_of_alias', List(path_root_id), None, None)
        ])
        test_union = Union('TestUnion', ns, None, None)
        test_union.set_attributes(None, [UnionField('test', path_root_id, None, None)])

        ns.add_data_type(test_struct)
        ns.add_data_type(test_union)

        struct_alias = Alias('StructAlias', ns, None)
        struct_alias.set_attributes(None, test_struct)

        ns.add_alias(struct_alias)

        api = remove_aliases_from_api(api)

        # Ensure namespace exists

def test_struct_with_custom_annotations(self):
        # type: () -> None
        ns = ApiNamespace('files')
        annotation_type = AnnotationType('MyAnnotationType', ns, None, [
            AnnotationTypeParam('test_param', Int32(), None, False, None, None)
        ])
        ns.add_annotation_type(annotation_type)
        annotation = CustomAnnotation('MyAnnotation', ns, None, 'MyAnnotationType',
            None, [], {'test_param': 42})
        annotation.set_attributes(annotation_type)
        ns.add_annotation(annotation)
        struct = Struct('MyStruct', ns, None)
        struct.set_attributes(None, [
            StructField('annotated_field', Int32(), None, None),
            StructField('unannotated_field', Int32(), None, None),
        ])
        struct.fields[0].set_annotations([annotation])

        result = self._evaluate_struct(ns, struct)

        expected = textwrap.dedent('''\
            class MyStruct(bb.Struct):

                __slots__ = [
                    '_annotated_field_value',
                    '_annotated_field_present',
                    '_unannotated_field_value',
                    '_unannotated_field_present',
                ]

                _has_required_fields = True

def test_union(self):

        ns = ApiNamespace('files')

        update_parent_rev = Struct(
            'UpdateParentRev',
            None,
            ns,
        )
        update_parent_rev.set_attributes(
            "Overwrite existing file if the parent rev matches.",
            [
                StructField('parent_rev', String(), 'The revision to be updated.', None)
            ],
        )
        update_parent_rev._add_example(
            AstExample(
                path=None,
                lineno=None,
                lexpos=None,
                label='default',
                text=None,
                fields={
                    'parent_rev': AstExampleField(
                        None,
                        None,
                        None,
                        'parent_rev',
                        'xyz123')}))

def _make_namespace_with_many_structs():
    # type: (...) -> ApiNamespace
    ns = ApiNamespace('ns_with_many_structs')

    struct1 = Struct(name='Struct1', namespace=ns, ast_node=None)
    struct1.set_attributes(None, [StructField('f1', Boolean(), None, None)])
    ns.add_data_type(struct1)

    struct2 = Struct(name='Struct2', namespace=ns, ast_node=None)
    struct2.set_attributes(
        doc=None,
        fields=[
            StructField('f2', List(UInt64()), None, None),
            StructField('f3', Timestamp(ISO_8601_FORMAT), None, None),
            StructField('f4', Map(String(), UInt64()), None, None)
        ]
    )
    ns.add_data_type(struct2)

    return ns

def _make_struct(struct_name, struct_field_name, namespace):
    # type: (typing.Text, typing.Text, ApiNamespace) -> Struct
    struct = Struct(name=struct_name, namespace=namespace, ast_node=None)
    struct.set_attributes(None, [StructField(struct_field_name, Boolean(), None, None)])
    return struct

def _make_namespace_with_many_structs():
    # type: (...) -> ApiNamespace
    ns = ApiNamespace('ns_with_many_structs')

    struct1 = Struct(name='Struct1', namespace=ns, ast_node=None)
    struct1.set_attributes(None, [StructField('f1', Boolean(), None, None)])
    ns.add_data_type(struct1)

    struct2 = Struct(name='Struct2', namespace=ns, ast_node=None)
    struct2.set_attributes(
        doc=None,
        fields=[
            StructField('f2', List(UInt64()), None, None),
            StructField('f3', Timestamp(ISO_8601_FORMAT), None, None),
            StructField('f4', Map(String(), UInt64()), None, None)
        ]
    )
    ns.add_data_type(struct2)

    return ns

# type: (...) -> ApiNamespace
    ns = ApiNamespace('ns_w_nested_types')

    struct = Struct(name='NestedTypes', namespace=ns, ast_node=None)
    struct.set_attributes(
        doc=None,
        fields=[
            StructField(
                name='NullableList',
                data_type=Nullable(
                    List(UInt64())
                ),
                doc=None,
                ast_node=None,
            ),
            StructField(
                name='ListOfNullables',
                data_type=List(
                    Nullable(UInt64())
                ),
                doc=None,
                ast_node=None,
            )
        ]
    )
    ns.add_data_type(struct)

    return ns