Laurus : Lexical Augmented Unified Retrieval Using Semantics

Laurus is a search core library written in Rust, designed for Information Retrieval with Semantics.

Laurus provides the foundational mechanisms essential for advanced search capabilities:

• Lexical search primitives for precise, exact-match retrieval
• Vector-based similarity search for deep semantic understanding
• Hybrid scoring and ranking to synthesize multiple signals into coherent results

Rather than functioning as a monolithic search engine, Laurus is architected as a composable search core — a suite of modular building blocks designed to be embedded into applications, extended with custom logic, or orchestrated within distributed systems.

Documentation

Comprehensive documentation is available in the docs/ directory and online at https://mosuka.github.io/laurus/:

• Getting Started: Installation and basic usage.
• Architecture: System architecture overview.
• Core Concepts: Schema, Analysis, Embeddings, and Storage.
• Indexing: Lexical and Vector indexing.
• Search: Lexical, Vector, and Hybrid search.
• Advanced Features: Query DSL, ID Management, Persistence, and Deletions.
• API Reference

Features

• Pure Rust Implementation: Memory-safe and fast performance with zero-cost abstractions.
• Hybrid Search: Seamlessly combine BM25 lexical search with HNSW vector search using configurable fusion strategies.
• Multimodal capabilities: Native support for text-to-image and image-to-image search via CLIP embeddings.
• Rich Query DSL: Term, phrase, boolean, fuzzy, wildcard, range, and geographic queries.
• Flexible Analysis: Configurable pipelines for tokenization, normalization, and stemming (including CJK support).
• Pluggable Storage: Interfaces for in-memory, file-system, and memory-mapped storage backends.

Quick Start

use laurus::lexical::{TermQuery, TextOption};
use laurus::{Document, Engine, LexicalSearchRequest, Schema, SearchRequestBuilder};
use laurus::storage::{StorageConfig, StorageFactory};
use laurus::storage::memory::MemoryStorageConfig;

#[tokio::main]
async fn main() -> laurus::Result<()> {
    // 1. Create storage
    let storage = StorageFactory::create(StorageConfig::Memory(MemoryStorageConfig::default()))?;

    // 2. Define schema
    let schema = Schema::builder()
        .add_text_field("title", TextOption::default())
        .add_text_field("body", TextOption::default())
        .build();

    // 3. Create engine
    let engine = Engine::new(storage, schema).await?;

    // 4. Index documents
    engine
        .add_document(
            "doc1",
            Document::builder()
                .add_text("title", "Introduction to Rust")
                .add_text("body", "Rust is a systems programming language focused on safety.")
                .build(),
        )
        .await?;
    engine
        .add_document(
            "doc2",
            Document::builder()
                .add_text("title", "Python for Data Science")
                .add_text("body", "Python is widely used in data science and machine learning.")
                .build(),
        )
        .await?;
    engine.commit().await?;

    // 5. Search
    let results = engine
        .search(
            SearchRequestBuilder::new()
                .lexical_search_request(LexicalSearchRequest::new(Box::new(TermQuery::new(
                    "body", "rust",
                ))))
                .build(),
        )
        .await?;

    for hit in &results {
        println!("[{}] score={:.4}", hit.id, hit.score);
    }

    Ok(())
}

Examples

You can find usage examples in the laurus/examples/ directory:

• Quickstart - Basic full-text search
• Lexical Search - All query types (Term, Phrase, Boolean, Fuzzy, Wildcard, Range, Geo, Span)
• Vector Search - Semantic similarity search with embeddings
• Hybrid Search - Combining lexical and vector search with fusion
• Multimodal Search - Text-to-image and image-to-image search
• Synonym Graph Filter - Synonym expansion in analysis pipeline
• Candle Embedder - Local BERT embeddings
• OpenAI Embedder - Cloud-based embeddings

Contributing

We welcome contributions!

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.