@hackage full-text-search0.2.2.2

In-memory full text search engine

An in-memory full text search engine library. It lets you run full-text queries on a collection of your documents.


  • Keyword queries and auto-complete/auto-suggest queries.

  • Can search over any type of "document". (You explain how to extract search terms from them.)

  • Supports documents with multiple fields (e.g. title, body)

  • Supports documents with non-term features (e.g. quality score, page rank)

  • Uses the state of the art BM25F ranking function

  • Adjustable ranking parameters (including field weights and non-term feature scores)

  • In-memory but quite compact. It does not keep a copy of your original documents.

  • Quick incremental index updates, making it possible to keep your text search in-sync with your data.

It is independent of the document type, so you have to write the document-specific parts: extracting search terms and any stop words, case-normalisation or stemming. This is quite easy using libraries such as tokenize and snowball.

The source package includes a demo to illustrate how to use the library. The demo is a simplified version of how the library is used in the hackage-server where it provides the backend for the package search feature.