A very simple custom RDoc generator

simple_rdoc.rb

# RDoc can use a custom generator but it isn't that well documentated. Here is a
# sample custom generator to get you going.
#
# Ruby comes with an `rdoc` executable but most of us generate our docs via Rake. To
# use your custom generator with Rake do something like the following in your Rakefile..
#
#   require 'rdoc/task'
#   require 'simple_rdoc'
#   
#   RDoc::Task.new('simple_doc') do |i|
#     i.generator = 'simple'
#   end
#
# And run it with..
#
#   rake simple_doc
#

require 'rdoc'
require 'erb'

module RDoc
  module Generator
    class Simple
      ::RDoc::RDoc.add_generator self

      def initialize(store, options)
        @store = store
        @options = options
      end

      def generate
        # @store contains the parsed rdoc tree.  As well as #all_classes_and_modules
        # there are other ways to dip into the tree in https://github.com/rdoc/rdoc/blob/master/lib/rdoc/store.rb
        @methods = @store.all_classes_and_modules.uniq.map(&:method_list).flatten

        File.open('index.html', 'w') do |file|
          file << ERB.new(File.read(template_path)).result(binding)
        end
      end

      # when processing the markup it expects to find these methods
      def class_dir; nil; end
      def file_dir; nil; end

      private

      def template_path
        File.join(File.dirname(__FILE__), 'simple.html.erb')
      end
    end
  end
end