Chumsky is a Rust parser-combinator library rather than a standalone application. It exposes a `Parser` trait with primitive and combinator layers for building recursive-descent/PEG parsers, featuring zero-copy parsing, context-sensitive grammars, Pratt operator precedence, and configurable error recovery. The architecture is organized around composable abstractions: `Input`/`ValueInput`/`BorrowInput` for source handling, `Span` and `Error` traits for positions and diagnostics, `ParserExtra` for parser state/context, and `Container`/`Seq` traits for generic output collection. The main entry points are the public API in `src/lib.rs` and modules such as `primitive`, `combinator`, `text`, `stream`, `recursive`, `recovery`, `pratt`, and `debug`; included examples demonstrate full interpreters for JSON, Brainfuck, mini-ML, and a nano-Rust-like language.
Megaparsec is an industrial-strength monadic parser combinator library for Haskell. It provides a feature-rich balance between speed, flexibility, and quality of parse errors. The library supports parsing String, ByteString, and Text (both strict and lazy) input streams, with sophisticated error reporting that includes source code position highlighting, custom error components, and bundled error messages. It includes utilities for whitespace and comment handling, indentation-sensitive grammars, and lexing of numbers and literals. The architecture is modular, with core parsing functionality in Text.Megaparsec and specialized modules for byte/char processing, error handling, and lexing.