# How-to guides

Task-oriented recipes. Each one assumes you already know the basics (if not, start
with the {doc}`../tutorial/parse-your-first-header`) and shows how to accomplish a
specific goal.

- {doc}`validate-input` — check that a string conforms to a grammar.
- {doc}`extract-values-with-visitors` — pull data out of a parse tree.
- {doc}`load-a-grammar-from-a-file` — parse with a grammar kept in a `.abnf` file.
- {doc}`write-your-own-grammar-module` — define a grammar, including importing rules
  from another.
- {doc}`use-the-rust-backend` — install, force, and build the optional Rust backend.