qexpr

Typed query expressions (query algebra) for retrieval systems.

Semantics

• Associativity: And/Or are n-ary and associative. Flattening is allowed.
• Duplicates: And([A, A]) is semantically equivalent to And([A]) (set semantics), but the AST preserves them.
• Empty: And([]) is True (universe); Or([]) is False (empty set).

What it is

This crate is intentionally not a parser. Parsing is product-specific. The goal here is a small, stable AST for query meaning that multiple systems can compile into their own execution plans.

Usage

[dependencies]
qexpr = "0.1.0"

Example:

use qexpr::{Near, Phrase, QExpr, Term};

let q = QExpr::And(vec![
    QExpr::Term(Term::new("alpha")),
    QExpr::Phrase(Phrase::new(vec![Term::new("new"), Term::new("york")])),
    QExpr::Near(Near::new(vec![Term::new("deep"), Term::new("learning")], 5, false)),
]);

qexpr::validate(&q).unwrap();

Development

cargo test