Perlin is a free and open-source document search engine library build on top of perlin-core.
Since the first release no stone was left untouched. The then-perlin was moved to perlin-core and it will be replaced by a more top-level library. This new perlin aims to provide a user-friendly abstraction around perlin-core for document search engines.
The documentation for version 0.1 can be found at https://doc.perlin-ir.org/v0.1/perlin/index.html and the code is available at the 'v0.1' tag.