Crate haystack_core 

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();

Modules

auth

SCRAM SHA-256 authentication primitives for the Haystack auth protocol.

codecs

Haystack wire format codecs for serialization and deserialization.

data

Haystack data collection types.

expr

Expression evaluator for arithmetic/logic expressions over entity tags.

filter

Haystack filter expression parser and evaluator.

graph

In-memory entity graph with indexed querying, change tracking, and thread-safe access.

kinds

Haystack type system — the Kind enum and its 15 scalar types.

ontology

Haystack 4 ontology layer — defs, taxonomy, conjuncts, and validation.

xeto