html_builder.rb

require 'cgi/util'
require 'cgi/html'

ch5 = CGI::HTML5.new
puts ch5.instance_eval {
  html {
    head {
      title { "XML encoding with Ruby" }
    } +
    body {
      h1 { "XML encoding with Ruby" } +
      p  { "this format can be used as an alternative markup to XML" } +
      a(href: "https://www.ruby-lang.org/") { "Ruby"  } +

      p {
        "This is some" +
        b { "mixed" } +
        "text. For more see the" +
        a(href: "https://www.ruby-lang.org/") { "Ruby"  } +
        "project"
      }
    }
  }
}