Struct Grouping 

pub struct Grouping {
    pub keys: Vec<String>,
    pub by: Option<Grain>,
}

What a grouped arrangement sorts entries into groups by.

prov’s own, not a mirror of it. This used to be a redeclaration — the crate sits below the workspace layer and must stay portable to wasm32-unknown-unknown, so it kept its own DateGrain and Grouping with the spellings and prefix lengths copied across, on the reasoning that a site grouped “by year” must cut dates the same way the app’s lens does or the published archive reads differently from the vault it came from.

Since prov 0.5 the grouping engine is prov-views, which reaches nothing that can write and is already in this crate’s dependency graph. So the way to keep the two identical is to stop having two: the published site now groups through the same Grouping::keys_of the vault does, and “identical” is a fact rather than a promise two copies make to each other. What a view sorts records by — MoReq2010’s classification.

One shape, not a set of blessed kinds: an ordered chain of field keys, and an optional grain to cut the chosen value at. See the module docs for why there is no date variant.

Fields

keys: Vec<String>

The field paths to read, in order — the first that carries a value wins, and supplies all of that view’s group keys for the document. Each is a path as a fields declaration writes one (people, written.on, confirmed[].by), so a view groups by a key inside a mapping or inside every item of a list, not only by a top-level key. Guaranteed non-empty by ViewSpec::parse.

by: Option<Grain>

The grain the chosen value is cut at, or None to group on the value itself.

Implementations

impl Grouping

pub fn field(key: impl Into<String>) -> Grouping

A view grouped on one field’s raw values.

pub fn keys_of(&self, meta: &Value) -> Vec<String>

The group keys meta falls under — empty when no field in the chain carries a usable value, which is the ungrouped bucket.

A sequence-valued field yields one key per element, so a letter about two people appears under both. That is the whole point of a view: the same document reached several ways, with retrieval decoupled from the single containment spine.

The chain stops at the first key that is present and non-empty, and its values are used even if the grain rejects all of them. Falling through to created because date_of_document held something unparseable would silently file the document under a date it does not claim; leaving it ungrouped shows the bad value instead.

Trait Implementations

impl Clone for Grouping

fn clone(&self) -> Grouping

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Grouping

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Eq for Grouping

impl PartialEq for Grouping

fn eq(&self, other: &Grouping) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for Grouping