Comby vs OpenRewrite

Comby is a free, open-source tool for searching and changing code structure with lightweight templates. It recognizes basic syntax in code, strings, and comments across many languages, with parsers listed for C/C++, C#, Go, Java, JavaScript, Python, Rust, Swift, and TypeScript, plus a generic matcher for other formats. The project targets large refactors and one-off changes, and an interactive review mode lets users inspect proposed edits. Comby can run from its command line, Python bindings, or HTTP requests sent to a server on your machine. Installation instructions cover macOS with Homebrew, Ubuntu, Windows through Ubuntu on WSL, and Docker; building from source is also described. Linked projects include an Emacs package and a prototype VS Code extension. Other uses include structural code search, compiler fuzzing, test-case reduction, editor find and replace, and academic research. Comby matches balanced delimiters while accounting for comments and string literals, and supports regex search. It is self-hosted and available for API, Linux, macOS, and Windows use. The Apache-2.0 license is identified in the public repository.

OpenRewrite is an open-source ecosystem for automated code refactoring, aimed at updating code and reducing technical debt. It represents code as Lossless Semantic Trees, applies transformations, and prints the result back into source code for review. Its recipes cover framework migrations, security fixes, and style consistency, and can be written in YAML, Refaster templates, or Java. Maven and Gradle plugins run recipes locally as part of builds, one repository at a time. The Maven plugin offers a dry run that reports potential changes and writes diff files; recipes run only when explicitly activated by name. Documented support includes Java, Kotlin, and Groovy, plus formats such as HCL, JSON, Properties, Protobuf, TOML, XML, and YAML. Framework coverage includes Spring, Quarkus, and Micronaut. The recipe index lists 4,183 recipes across modules. Core and language libraries use Apache License 2.0, but some recipes have other licensing terms. Core is free; some artifacts require authenticated repository access, and some recipes require a Moderne subscription.