18 releases (4 breaking)

Uses new Rust 2024

0.7.2	Mar 3, 2026
0.7.1	Mar 3, 2026
0.6.3	Mar 2, 2026
0.5.4	Mar 2, 2026
0.3.2	Mar 1, 2026

#775 in Encoding

Used in 3 crates

MIT license

1MB
22K SLoC

Haystack Core

Rust implementation of the Project Haystack data model, codecs, filter engine, entity graph, ontology system, and SCRAM SHA-256 authentication.

Crate Organization

Module	Description
`kinds`	Central value type (`Kind`) with 15 scalar types (Marker, Number, Str, Ref, etc.)
`data`	Collection types: `HDict` (tag map), `HGrid` (table), `HCol`, `HList`
`codecs`	Wire format codecs: Zinc, Trio, JSON, Haystack JSON v3, CSV, and RDF (Turtle/JSON-LD)
`filter`	Haystack filter expression parser and evaluator (`site and area > 1000`)
`graph`	In-memory entity graph with bitmap tag indexes, B-tree value indexes, ref adjacency, CSR, and change tracking
`ontology`	Haystack 4 def/lib/namespace system with taxonomy, validation, and Xeto support
`auth`	SCRAM SHA-256 authentication per the Haystack auth specification
`xeto`	Xeto schema language parser and structural type fitting

Quick Start

use haystack_core::data::{HDict, HGrid};
use haystack_core::kinds::{Kind, Number, HRef};
use haystack_core::graph::EntityGraph;
use haystack_core::codecs::codec_for;

// Build an entity
let mut site = HDict::new();
site.set("id", Kind::Ref(HRef::from_val("site-1")));
site.set("dis", Kind::Str("Main Campus".into()));
site.set("site", Kind::Marker);
site.set("area", Kind::Number(Number::unitless(50000.0)));

// Add to graph and query
let mut graph = EntityGraph::new();
graph.add(site).unwrap();
let results = graph.read_all("site and area > 1000", 0).unwrap();
assert_eq!(results.len(), 1);

// Encode to Zinc wire format
let zinc = codec_for("text/zinc").unwrap();
let grid = graph.to_grid("").unwrap();
let encoded = zinc.encode_grid(&grid).unwrap();

Dependencies

~12–18MB
~325K SLoC