markdown_fixer.rb

module Markdown
  module Fixer

    # Since gsub returns a replaced string, we can chain the methods together
    # without yielding the module itself

    def self.fix_all(markdown)
      markdown.gsub('title', '"title"')
              .gsub('hr', 'hhr')
              .gsub('\r\n', '\n')
              .gsub('tags', 't a g s')
    end

    def self.add_quotes_to_title(markdown)
      markdown.gsub('title', '"title"')
    end

    def self.modify_hr_tags(markdown)
      markdown.gsub('hr', 'hhr')
    end

    def self.convert_newlines(markdown)
      markdown.gsub('\r\n', '\n')
    end

    def self.split_tags(markdown)
      markdown.gsub('tags', 't a g s')
    end

  end
end

# Usage:

Markdown::Fixer.fix_all('title hr tags\r\n')

# returns: "title" hhr t a g s\n