Module winnow::_tutorial::chapter_0

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Chapter 0: Introduction

This tutorial assumes that you are:

  • Already familiar with Rust
  • Using winnow for the first time

The focus will be on parsing in-memory strings (&str). Once done, you might want to check the Special Topics for more specialized topics or examples.

About

winnow is a parser-combinator library. In other words, it gives you tools to define:

  • “parsers”, or functions that takes an input and gives back an output
  • “combinators”, or functions that take parsers and combine them together!

While “combinator” might be an unfamiliar word, you are likely using them in your rust code today, like with the Iterator trait:

let data = vec![1, 2, 3, 4, 5];
let even_count = data.iter()
    .copied()  // combinator
    .filter(|d| d % 2 == 0)  // combinator
    .count();  // combinator

Parser combinators are great because:

  • The parsers are small and easy to write
  • The parsers components are easy to reuse (if they’re general enough, please add them to winnow!)
  • The parsers components are easy to test separately (unit tests and property-based tests)
  • The parser combination code looks close to the grammar you would have written
  • You can build partial parsers, specific to the data you need at the moment, and ignore the rest

Re-exports