Enum ViewTree 

pub enum ViewTree {
    Leaf(Leaf),
    And(Box<Tree>, Box<Tree>),
    Or(Box<Tree>, Box<Tree>),
    Diff(Box<Tree>, Box<Tree>),
}

The composition tree. Depth ≤ 3, leaves ≤ 4 (declarative caps, enforced at CREATE).

use kevy_index::{IndexValue, Leaf, Segment, Tree};

let mut age = Segment::new();
age.set_key_dir(true);
age.apply(b"u:1", None, Some(IndexValue::I64(30)));
age.apply(b"u:2", None, Some(IndexValue::I64(70)));
let mut city = Segment::new();
city.set_key_dir(true);
city.apply(b"u:1", None, Some(IndexValue::Str(b"kyoto".to_vec())));
city.apply(b"u:2", None, Some(IndexValue::Str(b"kyoto".to_vec())));

let kyoto = IndexValue::Str(b"kyoto".to_vec());
let t = Tree::And(
    Box::new(Tree::Leaf(Leaf::new("city", kyoto.clone(), kyoto))),
    Box::new(Tree::Leaf(Leaf::new("age", IndexValue::I64(18), IndexValue::I64(65)))),
);
let seg = |name: &[u8]| match name {
    b"age" => Some(&age),
    b"city" => Some(&city),
    _ => None,
};
assert_eq!(t.eval(&seg), vec![b"u:1".to_vec()]);
assert!(t.contains(b"u:1", &seg) && !t.contains(b"u:2", &seg));
assert_eq!((t.leaves(), t.depth()), (2, 2));

let mut names = Vec::new();
t.each_leaf(&mut |l: &Leaf| names.push(l.index.clone()));
assert_eq!(names, [b"city".to_vec(), b"age".to_vec()]);

Variants

Leaf(Leaf)

A single index shape.

use kevy_index::{IndexValue, Leaf, Tree};
let t = Tree::Leaf(Leaf::new("age", IndexValue::I64(0), IndexValue::I64(9)));
assert_eq!((t.leaves(), t.depth()), (1, 1));

And(Box<Tree>, Box<Tree>)

Intersection.

use kevy_index::{IndexValue, Leaf, Tree};
let leaf = |lo, hi| Box::new(Tree::Leaf(Leaf::new("n", IndexValue::I64(lo), IndexValue::I64(hi))));
let t = Tree::And(leaf(0, 10), leaf(5, 20));
assert!(t.contains_values(&|_: &[u8]| Some(IndexValue::I64(7))));
assert!(!t.contains_values(&|_: &[u8]| Some(IndexValue::I64(3))));

Or(Box<Tree>, Box<Tree>)

Union.

use kevy_index::{IndexValue, Leaf, Tree};
let leaf = |lo, hi| Box::new(Tree::Leaf(Leaf::new("n", IndexValue::I64(lo), IndexValue::I64(hi))));
let t = Tree::Or(leaf(0, 1), leaf(8, 9));
assert!(t.contains_values(&|_: &[u8]| Some(IndexValue::I64(9))));
assert!(!t.contains_values(&|_: &[u8]| Some(IndexValue::I64(5))));

Diff(Box<Tree>, Box<Tree>)

Left minus right (NOT commutative — order is fixed).

use kevy_index::{IndexValue, Leaf, Tree};
let leaf = |lo, hi| Box::new(Tree::Leaf(Leaf::new("n", IndexValue::I64(lo), IndexValue::I64(hi))));
let t = Tree::Diff(leaf(0, 10), leaf(5, 10));
assert!(t.contains_values(&|_: &[u8]| Some(IndexValue::I64(4))));
assert!(!t.contains_values(&|_: &[u8]| Some(IndexValue::I64(6))));

Implementations

impl Tree

pub fn eval<'a>( &self, seg: &impl Fn(&[u8]) -> Option<&'a Segment>, ) -> Vec<Vec<u8>>

Evaluate tree against one shard’s segments: seg resolves an index name to its Segment (None = unknown index → empty leaf — the runtime validates names at CREATE, so this is defensive). Returns the member keys (unordered set semantics).

use kevy_index::{IndexValue, Leaf, Segment, Tree};
let mut age = Segment::new();
age.set_key_dir(true);
age.apply(b"u:1", None, Some(IndexValue::I64(30)));
age.apply(b"u:2", None, Some(IndexValue::I64(70)));
let t = Tree::Leaf(Leaf::new("age", IndexValue::I64(18), IndexValue::I64(65)));
let seg = |name: &[u8]| (name == b"age").then_some(&age);
assert_eq!(t.eval(&seg), vec![b"u:1".to_vec()]);
assert!(t.contains(b"u:1", &seg) && !t.contains(b"u:2", &seg));

pub fn contains<'a>( &self, key: &[u8], seg: &impl Fn(&[u8]) -> Option<&'a Segment>, ) -> bool

Re-evaluate ONE key’s membership (the materialized write hook): every leaf is a point probe in the segment’s key directory (Segment::set_key_dir); a segment without one holds no key.

pub fn contains_values( &self, vals: &impl Fn(&[u8]) -> Option<IndexValue>, ) -> bool

Tree::contains variant over PRE-FETCHED per-index values — the write hook probes each referenced index ONCE per key and evaluates every view against the same small table (bounds compares only; no per-view re-hashing).

use kevy_index::{IndexValue, Leaf, Tree};
let t = Tree::Leaf(Leaf::new("age", IndexValue::I64(18), IndexValue::I64(65)));
assert!(t.contains_values(&|_: &[u8]| Some(IndexValue::I64(40))));
assert!(!t.contains_values(&|_: &[u8]| None));

pub fn leaves(&self) -> usize

Number of leaves.

pub fn depth(&self) -> usize

Depth (a leaf is 1).

pub fn each_leaf<F>(&self, f: &mut F)

where F: FnMut(&Leaf),

Visit every leaf.

Trait Implementations

impl Clone for Tree

fn clone(&self) -> Tree

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Tree

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

Formats the value using the given formatter.

impl PartialEq for Tree

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Tree