# The Expressions Module for Apache Lucene

The expressions module is new to Lucene 4.6. It provides an API for dynamically computing per-document values based on string expressions.

The module is organized in two sections:

1. {@link org.apache.lucene.expressions} - The abstractions and simple utilities for common operations like sorting on an expression
2. {@link org.apache.lucene.expressions.js} - A compiler for a subset of JavaScript expressions

For sample code showing how to use the API, see {@link org.apache.lucene.expressions.Expression}.