Porting hiccup clj library to ruby

hiccup.rb

module Hiccup
  extend self

  def html(body)
    parse(body)
  end

  private

  def parse(body)
    if body.first.class != Symbol
      return nil if body.empty? || body.nil?
      return body.first,        parse(rest(body).flatten(1)) unless body.first.respond_to?(:each)
      return parse(body.first), parse(rest(body).flatten(1))
    else
      tag_tree(get_tag_name(body.first), *get_attrs_and_body(rest(body), parse_shorthand(body.first)))
    end
  end

  def tag_tree(name, attrs, body)
    if self_closing_tags.include?(name)
      tag(name, attrs).gsub('>', ' />')
    else
      [tag(name, attrs), body, "</#{name}>"].join
    end
  end

  def get_attrs_and_body(tail, shorthand)
    return to_attrs(tail.first.merge(shorthand)), parse(rest(tail)) if options_has_present?(tail)
    return to_attrs(shorthand),                   parse(tail)
  end

  def options_has_present?(tail)
    tail.first.respond_to?(:keys)
  end

  def get_tag_name(elem)
    elem.to_s.split(/[\.#]/).first
  end

  def tag(name, *attrs)
    "<#{name}#{attrs.join}>"
  end

  def parse_shorthand(tag)
    Shorthand[tag]
      .expand_class
      .expand_id
      .split(':')
      .drop(1)
      .each_slice(2)
      .inject({}) do |acc, (k,v)|
        acc.merge({k => v}) { |_,o,n| Array(o) << n }
      end
  end

  require 'delegate'
  class Shorthand < SimpleDelegator
    def self.[](str)
      new(str)
    end

    def initialize(str)
      @str = str.to_s
      super(@str)
    end

    def expand_class
      new @str.gsub('.',':class:')
    end

    def expand_id
      new @str.gsub('#',':id:')
    end

    def new(str)
      self.class.new(str)
    end

  end

  def rest(elem)
    elem.drop(1)
  end

  def to_attrs(hash)
    hash.map { |k, v| " #{k}=\"#{Array(v).join(' ')}\"" }
  end

  def self_closing_tags
    %w(area base br col colgroup command embed hr img input keygen link meta param source track wbr)
  end

end

if $0 !~ /rspec/
  begin require 'pry'; binding.pry rescue Gem::LoadError end
else
  new_lines_and_whitespace_not_in_a_tag = /\n\s+(?!\[^<>\]*)/
  describe Hiccup do
    context 'converts ruby syntax to html string' do
      it { expect(Hiccup.html [:script]).to eq "<script></script>" }
      it { expect(Hiccup.html [:p, "hello"]).to eq "<p>hello</p>" }
      it { expect(Hiccup.html [:p, [:em, "hello"]]).to eq "<p><em>hello</em></p>" }
      it { expect(Hiccup.html [:span, {:class => "foo"}, "bar"]).to eq "<span class=\"foo\">bar</span>" }
      it { expect(Hiccup.html [:div, {id: "email", class: "selected starred"}, "..."]).to eq "<div id=\"email\" class=\"selected starred\">...</div>" }
      it { expect(Hiccup.html [:a, {:href => "http://github.com"}, "GitHub"]).to eq "<a href=\"http://github.com\">GitHub</a>"}
      context 'self closing tags' do
        it { expect(Hiccup.html [:br]).to eq "<br />" }
        it { expect(Hiccup.html [:link]).to eq "<link />" }
        it { expect(Hiccup.html [:colgroup, {span: 2}]).to eq "<colgroup span=\"2\" />" }
        it { expect(Hiccup.html [:div, [:p], [:br]]).to eq "<div><p></p><br /></div>" }
      end
      context 'collections' do
        it { expect(Hiccup.html [:ul, ['a','b'].map { |x| [:li, x]}]).to eq "<ul><li>a</li><li>b</li></ul>"}
        it { expect(Hiccup.html [:ul, (11...13).map { |n| [:li, n]}]).to eq "<ul><li>11</li><li>12</li></ul>"}
      end
      context 'css shorthand' do
        it { expect(Hiccup.html [:'p.hi', "hello"]).to eq "<p class=\"hi\">hello</p>" }
        it { expect(Hiccup.html [:'p#hi', "hello"]).to eq "<p id=\"hi\">hello</p>" }
        it { expect(Hiccup.html [:'p.hi.greet.left', "hello"]).to eq "<p class=\"hi greet left\">hello</p>" }
        it { expect(Hiccup.html [:'p#hi.greet.left', "hello"]).to eq "<p id=\"hi\" class=\"greet left\">hello</p>" }
      end
      context 'different shaped trees' do
        it { expect(Hiccup.html [:p, "Hello ", [:em, "World!"]]).to eq "<p>Hello <em>World!</em></p>" }
        it { expect(Hiccup.html [:div, [:p, "Hello"], [:em, "World!"]]).to eq "<div><p>Hello</p><em>World!</em></div>" }
      end
    end
    it { expect(Hiccup.html [:html,
                              [:head,
                                [:title, "Hello World"]],
                              [:body,
                                [:header,
                                  [:'h1.header', "Hello World"],
                                    [:p, {id: 'why'}, "because we must."]]]]).to eq "
                            <html>
                              <head>
                                <title>Hello World</title>
                              </head>
                              <body>
                                <header>
                                  <h1 class=\"header\">Hello World</h1>
                                  <p id=\"why\">because we must.</p>
                                </header>
                              </body>
                            </html>".gsub(new_lines_and_whitespace_not_in_a_tag,'') }
  end
end

As far as I can tell. This script does everything that hiccup does currently, but drops all the extra features, and helper methods.

• css shorthand
• optional attributes
• self closing tags
• html as data