Discussion about item data source (for list_view, picker, etc)

[mofojed]

In the ui.picker spec:

ui.picker(
    *children: PickerItem | SectionElement | Table | PartitionedTable,
    key_column: ColumnName | None = None,
    label_column: ColumnName | None = None,
    description_column: ColumnName | None = None,
    icon_column: ColumnName | None = None,
    title_column: ColumnName | None = None,
    ...

Similarly, in ui.list_view spec:

ui.list_view(
    *children: ListViewItem | Table,
    key_column: ColumnName | None = None,
    label_column: ColumnName | None = None,
    description_column: ColumnName | None = None,
    icon_column: ColumnName | None = None,

All of those *_column arguments are only valid when the children passed in is a Table (or PartitionedTable) type.

What if we define a item_table_source that can be used in either, e.g.:

class ItemDataSource(TypedDict):
  table: Table | PartitionedTable
  key_column: ColumnName | None
  label_column: ColumnName | None
  description_column: ColumnName | None
  icon_column: ColumnName | None
  title_column: ColumnName | None
  actions: ListActionGroupElement | ListActionMenuElement | None

item_table_source(
  table: | Table | PartitionedTable,
  key_column: ColumnName | None = None,
  label_column: ColumnName | None = None,
  description_column: ColumnName | None = None,
  icon_column: ColumnName | None = None,
  title_column: ColumnName | None = None,
) -> ItemDataSource

ui.picker(
    *children: PickerItem | SectionElement | ItemDataSource,
)

ui.list_view(
    *children: PickerItem | SectionElement | ItemDataSource,
)

That way the args are only available when using a table as a data source.

[bmingles]

I like the item_table_source design. Only thing I'm on the fence about is whether this is the only supported way to provide the table data or if we should still support the original pattern as well.

[devinrsmith]

Is TableDataSource a better name? And then also, allow naked tables still?

ui.picker(
    *children: PickerItem | SectionElement | TableDataSource | Table | PartitionedTable,
)

It might also be worth thinking about type alias (modulo python version constraints):

type TableLikeType = Table | PartitionedTable
type PickableType = PickerItem | SectionElement | TableDataSource | TableLikeType

class TableDataSource(TypedDict):
  table: TableLikeType
  ...
  
ui.picker(
    *children: PickableType
)

[jnumainville]

I think we should still allow Table and PartitionedTable as they provide a really low friction path for the simple use cases. That's not to say allowing the same arguments beyond that - I think if we do this we want all the column variables in the data source only to reduce duplication.

[bmingles]

Another topic to throw in here is the actions prop. It currently is specified as ListActionGroupElement | ListActionMenuElement | None. The limitation here is that there is no way to dynamically render actions. Scenarios such as disabling or hiding an action that shouldn't be available for a particular item would not be possible since the ListActionGroupElement or ListActionMenuElement have no access to the item when rendering. We may want to consider actions taking a render function instead of an element. We could then pass the item to the render function so that it could do whatever it wanted based on the data.

[mofojed]

Implementation will be handled with #414