jaala

README

jaala

Jaala (Sanskrit for "network") is a small query engine for graph-shaped data.

Its first package, datalog, is a Datalog evaluator with stratified negation, recursion, aggregation and having, binding-pattern indexes, and provenance: every answer row carries the citations of the facts that produced it. It knows nothing about any particular domain.

It comes in two packages:

• ns is the vocabulary: one tree of dotted paths holding every name a query can call, with each name's signature. A leaf is a base relation whose facts some Source serves, a predicate the host computes, or a derived relation defined by a module. ns parses and evaluates nothing, and imports only the standard library, so a host's fact layer can register into it without taking on an engine.
• datalog is the engine. It provides Datalog as a module language, links the modules a query names, and evaluates queries over a vocabulary paired with one Source.

v, _ := ns.NewVocabulary(nil)                     // names only; no data
v.AddRelation("component.net", ns.Schema{Arity: 2, Labels: []string{"ref_des", "net"}})
v.AddRelation("component.class", ns.Schema{Arity: 2, Labels: []string{"ref_des", "class"}})
ns.StandardPredicates(v)                          // str.contains, str.prefix, ..., absent
v.AddLanguage(datalog.Language)
v.AddModule("net", datalog.LanguageName, `
# Nets that carry a test point.
has_test_point(?n: net) :- component.net(?tp, ?n), component.class(?tp, "test_point");
`)
if err := v.Check(); err != nil { ... }           // once, at load

base, err := datalog.NewBase(v, designSource)     // per dataset
rows, err := datalog.Naive{}.Eval(datalog.MustParse(`net.has_test_point(?n) => ?n`), base)

A query naming net.has_test_point pulls in the module that defines it. Each member carries a signature (argument names, entity kinds, scalar types and units), declared or inferred through its rules, which v.Lookup(path) returns for a host that lists and drills into what is available.

It started as the query engine inside agni, an EDA tooling engine, and was extracted so other graph tools could share it.

Both packages import only the Go standard library (and datalog imports ns), and build for GOOS=js GOARCH=wasm.

Licensed under Apache-2.0.