Understanding the duplication of the file tasks

In the previous chapter, we successfully created the blog builder. Let's revise the Rakefile that we've written to do it:

require_relative 'blog_generator'

articles = Rake::FileList.new('**/*.md',
                 '**/*.markdown') do |files|
             files.exclude('~*')
             files.exclude(/^temp.+\//)
             files.exclude do |file|
               File.zero?(file)
             end
           end

task :default => 'blog.html'

articles.ext.each do |article|
  file "#{article}.html" => "#{article}.md" do
    sh "pandoc -s #{article}.md -o #{article}.html"
  end

  file "#{article}.html" => "#{article}.markdown" do
    sh "pandoc -s #{article}.markdown -o #{article}.html"
  end
end

FileUtils.rm('blog.html', force: true)

file 'blog.html' => articles.ext('.html') do |t|
  BlogGenerator.new(t).perform
end

The following problems arise with the highlighted chunk of code:

• First of all, it contains the duplication of the...