They are not functions, but variables. Maybe this helps, as they basically are "selectors": https://text.marvinborner.de/2024-11-18-00.html#tagged-unions https:

They are not functions, but variables. Maybe this helps, as they basically are "selectors": https://text.marvinborner.de/2024-11-18-00.html#tagged-unions https://text.marvinborner.de/2024-11-18-00.html#tagged-union...