RPR displays Ruby's AST on command line.

rrg will read the source code of a Ruby project and generate a graph based on the require statements in the code; nodes represent the source files and an arrow from A to B means that A contains a `require 'B'` statement.

Takes parsed s-expressions for other languages and emits formatted ruby using ruby_scribe.

ruby2uml generates a UML Class diagram from Ruby source code.

Use codegraph to generate all kinds of graphviz graphs for you code, to visualize things like class hierarchy.

RubyCritic is a tool that wraps around various static analysis gems to provide a quality report of your Ruby code.

RubyLess is an interpreter for "safe ruby". The idea is to transform some "unsafe" ruby code into safe, type checked ruby, eventually rewriting some variables or methods.

See the summary.

A ruby formatting tool that takes S-expression as input and intelligently outputs formatted Ruby code.

RubyScript lets you write JavaScript code, in Ruby! It will convert Ruby code into JavaScript code for use on the web and elsewhere

RubyTodo allows you to have in-code todos and scan them to view the todos as a list

Ryan turns Ruby code files into objects that can describe themselves

KDEgettext.rb is a parser that extends ruby gettext to work with the Qt/KDE framework provided by korundum. It allows creating catalog files (po-file) with the GNU GetText format.

the secondbureau util gem

Complect churn and complexity (git commit count and Flog statistics)

Generates ruby from RubyParser-compatible S-expressions. It is a fork of ruby2ruby with slightly different goals.

Educational project exploring the utility in searching and manipulating codebases using S-expressions.

Locate module, class, or method defs by name in a project tree.

an interpreter of a subset of Ruby, written in Ruby

Translate Syntax Tree into other representations