Struct ListSectionsDriver 

pub struct ListSectionsDriver {
    pub key_at: Box<dyn Fn(usize) -> u64>,
    pub build: Box<dyn Fn(usize, RNode) -> BuiltRow>,
}

The section half the list() piece supplies (docs/list.md “Sections”): a key per item and a header builder. A header row precedes every item whose key differs from the item before.

Fields

key_at: Box<dyn Fn(usize) -> u64>

The section key of item index in the current snapshot (the piece snapshots keys with its rows, and rotates them with a committed move, so this needs no app access).

build: Box<dyn Fn(usize, RNode) -> BuiltRow>

Build the header of the section that starts at item first into anchor: the same contract as ListDriver::build, and its rebind writer takes the section’s first item.