GitHub - camping/mab: Markup as Ruby; fast, concise and feature-rich

Mab let's you write HTML in plain Ruby:

doctype!
html do
  head do
    link :rel => 'stylesheet', :href => 'style.css'
    script :src => 'jquery.js'
  end
  body :id => :frontpage do
    h1 'Hello World', :class => :main
  end
end

Syntax

1. Tags and Attributes

There are four basic forms:

tagname(content)

tagname(content, attributes)

tagname do
  content
end

tagname(attributes) do
  content
end

Example:

doctype!
html do
  head do
    link :rel => 'stylesheet', :href => 'style.css'
    script :src => 'jquery.js'
  end
  body :id => :frontpage do
    h1 'Hello World', :class => :main
  end
end

Which results in:

<!DOCTYPE html>
<html>
  <head>
    <link rel="stylesheet" href="style.css">
    <script src="jquery"></script>
  </head>
  <body id="frontpage">
    <h1 class="main">Hello World</h1>
  </body>
</html>

Notice how Mab knows that script tag must have content, so although you didn't specify anything it closed the tag for you.

2. Element Classes and IDs

You can easily add classes and IDs by hooking methods onto the container:

body.frontpage! do
  h1.main 'Hello World'
end

Which results in:

<body id="frontpage">
  <h1 class="main">Hello World</h1>
</body>

You can mix and match as you'd like (div.klass.klass1.id!), but you can only provide content and attributes on the last call:

# This is not valid:
form(:action => :post).world do
  input
end

# But this is:
form.world(:action => :post) do
  input
end

3. Escape or Not Escape

Mab uses a very simple convention for escaping: Strings as arguments gets escaped, strings in blocks don't:

div.comment "<script>alert(1)</script>"
# <div class="comment">&lt;script&gt;alert(1)&lt;/script&gt;</div>

div.comment { "I <strong>love</strong> you" }
# <div class="comment">I <strong>love</strong> you</div>

Be aware that Mab ignores the string in a block if there's other tags there:

div.comment do
  div.author "BitPuffin"
  "<p>Silence!</p>"
end

The p tag above won't appear in the output.

4. Text

Sometimes you need to insert plain text:

p.author do
  text 'Written by '
  a 'Bluebie', :href => 'http://creativepony.com/'
end

Which results in:

<p class="author">
  Written by
  <a href="http://creativepony.com/">Bluebie</a>
</p>

There's also text! which doesn't escape:

p.author do
  text! '<strong>Written</strong> by'
  a 'Bluebie', :href => 'http://creativepony.com/'

Invoking Mab

Using #mab:

require 'mab/kernel_method'

str = mab do
  doctype!
  html do
    # ...
  end
end

Using Mab::Builder (or Mab::PrettyBuilder if you want indentation):

class Person
  attr_reader :name

  def initialize(name)
    @name = name
  end

  def awesome?; true end
end

# Assign instance variables:
Mab::Builder.new(:person => Person.new('BitBuffin')) do
  if @person.awesome?
    h1 @person.name
  else
    p @person.name
  end
end.to_s

# Use helper (methods and instance variables will be available):
Mab::Builder.new({}, Person.new('BitPuffin')) do
  if awesome?
    h1 @name
  else
    p @name
  end
end.to_s

Extending an object (advanced usage):

r = Object.new
r.extend Mab::Mixin::HTML5
r.extend Mab::Indentation

r.mab do
  doctype!
  html do
    # ...
  end
end