pub type MapperMod<T> = Arc<dyn Fn(&mut Row, &mut T) -> Result<(), ExecError> + Send + Sync>;Expand description
The mapper-mod payload, pinned: after the base row struct is decoded, each
mapper mod reads more of the same Row into the struct — the prefixed
preload columns a same-query LEFT JOIN added.
This completes the wiring core’s QueryExtensions left open: core fixed
the mechanism with type-parameter payloads, keelson-exec pinned Hook
(ExecHook) and the raw-row Loader, and the mapper-mod payload was
explicitly deferred to Layer 2 “which owns the row-mapper it would modify”
— this is that row-mapper, so this is where the type gets pinned.
Aliased Type§
pub struct MapperMod<T> { /* private fields */ }