This package provides a RBTree is a sorted associative collection that is implemented with a Red-Black Tree. It maps keys to values like a Hash, but maintains its elements in ascending key order. The interface is the almost identical to that of Hash.

Kramdown is a library for parsing and converting a superset of Markdown. It is completely written in Ruby, supports standard Markdown (with some minor modifications) and various extensions that have been made popular by the PHP Markdown Extra package and Maruku.

This package provides a simple, fast MySQL library for Ruby, binding to libmysql.

minitest-rg changes the colour of the output from Minitest.

This gem generates a treemap showing the complexity of Ruby code on which it is run. It uses Saikuro under the covers to analyze Ruby code complexity.

Prawn is a pure Ruby PDF generation library.

Packnga is a library to translate to many languages using YARD.

Nokogiri (鋸) parses and searches XML/HTML, and features both CSS3 selector and XPath 1.0 support.

Contest allows writing declarative Test::Unit tests using nested contexts without performance penalties.

TZInfo is a Ruby library that provides daylight savings aware transformations between times in different time zones.

Standard is a port of StandardJS. Like StandardJS, it aims to save time in the following ways:

• No configuration.

• Automatically format code.

• Catch style issues and programmer errors early.

rainbow provides a string presenter object to colorize strings by wrapping them in ANSI escape codes.

queue_classic is a queuing library for Ruby applications (Rails, Sinatra, etc.) queue_classic features asynchronous job polling, database maintained locks and has a single dependency, pg.

Unicode::DisplayWidth is a Ruby library which can determine the display width of strings in Ruby.

This Ruby library provides a simple wrapper to bcrypt, a secure hash algorithm for hashing passwords.

Citrus is a parsing library for Ruby that combines the expressiveness of the language with the parsing expressions.

This package provides bindings for any kind of Ruby exceptions.

This package provides additional test assertions for Ruby standard libraries.

This package provides a common interface to multiple JSON libraries, including Oj, Yajl, the JSON gem (with C-extensions), the pure-Ruby JSON gem, NSJSONSerialization, gson.rb, JrJackson, and OkJson.

Ruby dubugging companion: pretty print Ruby objects to visualize their structure. Supports custom object formatting via plugins.

RangeCompresses is a tiny library that allows compressing arrays of objects into arrays of ranges. For example, it can turn the following: [1, 2, 3, 4, 6, 8, 9, 10] into [1..4, 6..6, 8..10].

Lumberjack is a simple logging utility that can be a drop in replacement for Logger or ActiveSupport::BufferedLogger. It provides support for automatically rolling log files even with multiple processes writing the same log file.

ChunkyPNG is a pure Ruby library that can read and write Portable Network Graphics (PNG) images without depending on an external image library. It tries to be memory efficient and reasonably fast. It has features such as:

• Decoding support for any image that the PNG standard allows. This includes all standard color modes, all bit depths, all transparency, and interlacing and filtering options.

• Encoding support for images of all color modes (true color, grayscale, and indexed) and transparency for all these color modes. The best color mode is chosen automatically, based on the amount of used colors.

• Read/write access to the image's pixels.

• Read/write access to all image metadata that is stored in chunks.

• Memory efficiency: fixnum are used, i.e. 4 or 8 bytes of memory per pixel, depending on the hardware).

• Performance: ChunkyPNG is reasonably fast for Ruby standards, by only using integer math and a highly optimized saving routine.

• Interoperability with RMagick.

ChunkyPNG is vulnerable to decompression bombs and can run out of memory when loading a specifically crafted PNG file. This is hard to fix in pure Ruby. Deal with untrusted images in a separate process, e.g., by using fork or a background processing library.

WEBrick is an HTTP server toolkit that can be configured as an HTTPS server, a proxy server, and a virtual-host server.