Records the results of every line of code in your file (intended to be like xmpfilter), inspired by Bret Victor's JavaScript example in his talk "Inventing on Principle"

Allows you to run Minitest tests and specs with RSpec's runner, thus you can write both Minitest and RSpec, side-by-side, and take advantage of the many incredibly helpful features it supports (primarily: better formatters, --colour, --fail-fast, and tagging).

A program to launch apps from the command-line

Hooks into program lifecycle to display error messages to you in a helpufl way, with inlined code, colour, and helpful heuristics about what might be the cause.