[Feature Request]: table function framework

[fengttt]

Is there an existing issue for the same feature request?

• [X] I have checked the existing issues.

Is your feature request related to a problem?

No response

Describe the feature you'd like

select * from table_function(...);

Esp, the following case is extremely useful -- return 1, 2, 3, 4, 5 ... select * from generate_series(start, end, step);

-- system or table information -- return zonemap info of the table select * from zonemap_info(tablename, column);

-- system function -- all current sessions (of this account). select * from current_sessions();

Describe implementation you've considered

Register system table functions, which can,

1. determine input param types.
2. check permission
3. report schema
4. impl, let's do generate_series first.

Documentation, Adoption, Use Case, Migration Strategy

No response

Additional information

No response