YARD -- Ruby Documentation Generation Tool

Quote from http://yardoc.org :

YARD is a documentation generation tool for the Ruby programming language. It enables the user to generate consistent, usable documentation that can be exported to a number of formats very easily, and also supports extending for custom Ruby constructs such as custom class level definitions.

Installation
YARD can be installed as a Ruby gem:

gem install yard

Usage
To see help on all commands:

yard help

Frequently Used Tags

@author
@param
@return
@note
@see
@todo

Document Generation

yard doc <Ruby file>

Examples:

Custom Tags
A custom tag can be added via one of the following:
(1) as a command option: --tag TAG:TITLE
(2) included in file .yardopts, e.g.