# predicates-core > Traits for **boolean-valued predicate functions** in Rust. [![Build Status](https://dev.azure.com/assert-rs/assert-rs/_apis/build/status/predicates-rs?branchName=master)](https://dev.azure.com/assert-rs/assert-rs/_build/latest?definitionId=1&branchName=master) [![Documentation](https://img.shields.io/badge/docs-master-blue.svg)](https://docs.rs/predicates-core) ![License](https://img.shields.io/crates/l/predicates-core.svg) [![Crates.io](https://img.shields.io/crates/v/predicates-core.svg?maxAge=2592000)](https://crates.io/crates/predicates-core) [Changelog](https://github.com/assert-rs/predicates-rs/blob/master/crates/core/CHANGELOG.md) ## License `predicates-core` is distributed under the terms of both the MIT license and the Apache License (Version 2.0). See LICENSE-APACHE, and LICENSE-MIT for details. ## Credits Big thanks to [futures-rs](https://github.com/alexcrichton/futures-rs), whose slick API design informed a lot of decisions made on the API design of this library.