kermit-parser

Datalog query parser for the Kermit workspace. Parses rules of the form

Head(…) :- Body1(…), Body2(…), …, BodyN(…).

into a JoinQuery AST. Built on winnow.

Syntax

• Variables start with an uppercase ASCII letter: X, Name, Var1.
• Atoms (ground constants) start with a lowercase ASCII letter: alice, edge.
• Placeholders are the bare underscore _; they match any value without binding.

Identifiers after the first character may include ASCII alphanumerics and _.

AST types

• JoinQuery — head: Predicate, body: Vec<Predicate>.
• Predicate — name: String, terms: Vec<Term>.
• Term — Var(String), Atom(String), Placeholder.

Parse via std::str::FromStr:

use kermit_parser::JoinQuery;
let q: JoinQuery = "path(X, Z) :- edge(X, Y), edge(Y, Z).".parse().unwrap();

Consumers

kermit-algos parses queries into variable orderings for Leapfrog Triejoin, and kermit-bench embeds queries in benchmark YAML definitions (see benchmarks/README.md).