Haml

<h2 id="history">History</h2>
<p>Haml was originally introduced by <a href="/facts/Hampton_Catlin/4PT2VDsa">Hampton Catlin</a> with its initial release in 2006 and his work was taken up by a few other people.<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> His motive was to make <a href="/facts/HTML/sSc3fT78">HTML</a> simpler, cleaner, and easier to use. Since 2006, it has been revised several times, and newer versions have been released. Until 2012, Natalie Weizenbaum was the primary maintainer of Haml, followed by Norman Clarke until 2015.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a> Natalie worked on making Haml usable in <a href="/facts/Ruby_(programming_language)/BeYSaPSR">Ruby</a> applications, while the branding and design were done by Nick Walsh.<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a>
</p><p>Version 2.2.0 was released in July 2009 with support for Ruby 1.9 and <a href="/facts/Ruby_on_Rails/aG5P6uon">Rails</a> 2.0 or above.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a> Version 3.0.0 was released in May 2010, adding support for Rails 3 and some performance improvements. The fourth major version broke compatibility with previous versions, only supporting Rails 3 and Ruby 1.8.7 or above, and marked the switch to semantic versioning. Several amendments like increasing the performance, fixing a few warnings, compatibility with latest versions of Rails, fixes in the documentation, and many more were made in the Haml 4 series.<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a> Version 5.0.0 was released in April 2017. It supports Ruby 2.0.0 or above and drops compatibility with Rails 3.<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a> A '<a href="/facts/Tracing_(software)/36dskvN5">trace</a>'<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a> option, which helps users to perform tracing on Haml template, has been added.
</p>
<h2 id="examples">Examples</h2>
<p>Haml markup is similar to <a href="/facts/Cascading_Style_Sheets/tA90XBQo">CSS</a> in syntax. For example, Haml has the same dot . representation for classes as CSS does.
</p>
<h3>"Hello, World!"</h3>
<h4>Haml as a <a href="/facts/Command-line_interface/R9JpGmXQ">command-line tool</a></h4>
<p>The following are equivalent as HAML recognises <a href="/facts/Cascading_Style_Sheets/tA90XBQo">CSS selectors</a>:
</p>
%p{:class => "sample", :id => "welcome"} Hello, World!

%p.sample#welcome Hello, World!

<p>These render to the following <a href="/facts/HTML/sSc3fT78">HTML</a> code:
</p>
<p class="sample" id="welcome">Hello, World!</p>

<h4>Haml as an add-on for <a href="/facts/Ruby_on_Rails/aG5P6uon">Ruby on Rails</a></h4>
<p>Haml can be integrated into <a href="/facts/Ruby_on_Rails/aG5P6uon">Ruby on Rails</a> as a plugin. Similar to <a href="/facts/ERuby/SfQFc10o">eRuby</a>, Haml also can access local variables (declared within same file in Ruby code). This example uses a sample Ruby controller file.<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a>
</p>
<ul><li>file: app/controllers/messages_controller.rbclass MessagesController < ApplicationController
  def index
    @message = "Hello, World!"
  end
end
</li>
<li>file: app/views/messages/index.html.haml#welcome
    %p= @message
</li></ul>
<p>This renders to:
</p>
<div id="welcome">
    <p>Hello, World!</p>
</div>

<h4>Haml as a Ruby module</h4>
<p>Haml is also capable of being used independently as a Ruby <a href="/facts/Library_(computing)/xRzL3P7q">library</a>.
</p>
welcome = Haml::Engine.new("%p Hello, World!")
welcome.render

<p>Output:
</p>
<p>Hello, World!</p>

<p><a href="http://haml.info/docs/yardoc/Haml/Engine.html">Haml::Engine</a> is a Haml class.
</p>
<h3>Basic example</h3>
<p>Haml uses whitespace indentation (two spaces) for tag nesting and scope, replacing open-end tag pairs. The following example compares the syntaxes of Haml and <a href="/facts/ERuby/SfQFc10o">eRuby</a> (Embedded Ruby), alongside the HTML output.
</p>
<table><tbody><tr><th>Haml</th><th>ERB</th><th>HTML</th></tr><tr><td>%div.category    %div.recipes        %h1= recipe.name        %h3= recipe.category    %div        %h4= recipe.description</td><td><div class="category">    <div class="recipes">        <h1><%= recipe.name %></h1>        <h3><%= recipe.category %></h3>    </div>    <div>        <h4><%= recipe.description %></h4>    </div></div></td><td><div class="category">    <div class="recipes">        <h1>Cookie</h1>        <h3>Desserts</h3>    </div>    <div>        <h4>Made from dough and sugar. Usually circular in shape and has about 400 calories.</h4>    </div></div></td></tr></tbody></table>
<p>Key differences are:
</p>
<ul><li>Haml doesn't have both opening and closing tags for each element like <a href="/facts/ERuby/SfQFc10o">eRuby</a>.</li>
<li><a href="/facts/ERuby/SfQFc10o">eRuby</a> syntax looks a lot like <a href="/facts/HTML/sSc3fT78">HTML</a> and is thereby more HTML-like while Haml is more <a href="/facts/Cascading_Style_Sheets/tA90XBQo">CSS</a>-like.</li>
<li>Haml uses <a href="/facts/Indent_style/m1DGdgyC">indentation</a> to nest tag elements whereas eRuby uses the same HTML representation.</li>
<li>In Haml properties like class, id can be represented by ., # respectively instead of regular class and id keywords. Haml also uses % to indicate a HTML element instead of <> as in eRuby.</li></ul>
<h3>Example with embedded Ruby code</h3>
!!!
%html{ :xmlns => "http://www.w3.org/1999/xhtml", :lang => "en", "xml:lang" => "en"}
  %head
    %title BoBlog
    %meta{"http-equiv" => "Content-Type", :content => "text/html; charset=utf-8"}
    %link{"rel" => "stylesheet", "href" => "main.css", "type" => "text/css"}
  %body
    #header
      %h1 BoBlog
      %h2 Bob's Blog
    #content
      - @entries.each do |entry|
        .entry
          %h3.title= entry.title
          %p.date= entry.posted.strftime("%A, %B %d, %Y")
          %p.body= entry.body
    #footer
      %p
        All content copyright © Bob

<p>The above Haml would produce this <a href="/facts/XHTML/6qHnmJSg">XHTML</a>:
</p>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html lang='en' xml:lang='en' xmlns='http://www.w3.org/1999/xhtml'>
  <head>
    <title>BoBlog</title>
    <meta content='text/html; charset=utf-8' http-equiv='Content-Type' />
    <link href="/stylesheets/main.css" media="screen" rel="Stylesheet" type="text/css" />
  </head>
  <body>
    <div id='header'>
      <h1>BoBlog</h1>
      <h2>Bob's Blog</h2>
    </div>
    <div id='content'>
      <div class='entry'>
        <h3 class='title'>Halloween</h3>
        <p class='date'>Tuesday, October 31, 2006</p>
        <p class='body'>
          Happy Halloween, glorious readers! I'm going to a party this evening... I'm very excited.
        </p>
      </div>
      <div class='entry'>
        <h3 class='title'>New Rails Templating Engine</h3>
        <p class='date'>Friday, August 11, 2006</p>
        <p class='body'>
          There's a new Templating Engine out for Ruby on Rails. It's called Haml.
        </p>
      </div>
    </div>
    <div id='footer'>
      <p>
        All content copyright © Bob
      </p>
    </div>
  </body>
</html>

<h2 id="implementations">Implementations</h2>
<p>The official implementation of Haml has been built for <a href="/facts/Ruby_(programming_language)/BeYSaPSR">Ruby</a> with plugins for <a href="/facts/Ruby_on_Rails/aG5P6uon">Ruby on Rails</a> and <a href="/facts/Merb/dE1dIVgJ">Merb</a>, but the Ruby implementation also functions independently. Haml can be easily used along with other languages. Below is a list of languages in which Haml has implementations:
</p>
<ul><li>Ruby: <a href="https://github.com/k0kubun/hamlit">hamlit</a></li>
<li>PHP: <a href="https://web.archive.org/web/20100303124319/http://wiki.github.com/dxw/Fammel/">Fammel</a>, <a href="http://phaml.sourceforge.net/">pHAML</a>, <a href="https://code.google.com/p/phamlp/">phamlp</a>, <a href="http://phphaml.sourceforge.net">phpHaml</a> (PHP 5), <a href="https://web.archive.org/web/20110417115303/http://haml-to-php.com/">HAML-TO-PHP</a> (PHP 5), <a href="https://github.com/arnaud-lb/MtHaml">Multi target HAML</a> (PHP 5.3)</li>
<li>JavaScript: <a href="https://github.com/creationix/haml-js">haml-js</a></li>
<li>Python: <a href="https://github.com/jessemiller/HamlPy">HamlPy</a></li>
<li>Common Lisp: <a href="https://github.com/Unspeakable/cl-haml">cl-haml</a></li>
<li>Dart: <a href="https://github.com/lvivski/hart">Hart</a></li>
<li>Java: <a href="https://github.com/raymyers/JHaml">JHaml</a></li>
<li>Lua: <a href="https://github.com/norman/lua-haml">LuaHaml</a></li>
<li>.NET: <a href="https://code.google.com/p/nhaml/">NHaml</a>
<ul><li>ASP.NET: <a href="https://web.archive.org/web/20080608081951/http://weblogs.asp.net/mirvodasergey/archive/2008/06/02/introducing-monorail-nhaml.aspx">MonoRail NHaml</a></li></ul></li>
<li>Perl: <a href="https://metacpan.org/module/Text::Haml">Text::Haml</a></li>
<li>Scala: <a href="https://web.archive.org/web/20100216131951/http://scalate.fusesource.org/index.html">Scalate</a></li></ul>
<h2 id="see-also">See also</h2>
<ul>
<li>Free and open-source software portal</li></ul>
<ul><li><a href="/facts/BBCode/gBcWXKgD">BBCode</a></li>
<li><a href="/facts/ERuby/SfQFc10o">eRuby</a></li>
<li><a href="/facts/Markaby/xYSpIFDc">Markaby</a></li>
<li><a href="/facts/Ruby_(programming_language)/BeYSaPSR">Ruby</a></li>
<li><a href="/facts/Ruby_on_Rails/aG5P6uon">Ruby on Rails</a></li>
<li><a href="/facts/YAML/mAY10H2Y">YAML</a></li>
<li><a href="/facts/Sass_(style_sheet_language)/qsc3Bw3W">Sass</a> – a similar system for <a href="/facts/Cascading_Style_Sheets/tA90XBQo">CSS</a>, also designed by Catlin.</li>
<li>Website Meta Language – another template language with similar functionalities</li>
<li><a href="/facts/Web_template/zWstHsCF">Web template</a> – general concept of template to <a href="/facts/HTML/sSc3fT78">HTML</a> expansion</li></ul>

<h2 id="external-links">External links</h2>
<ul><li><a href="https://haml.info">Official website</a> 
<ul><li><a href="http://haml.info/tutorial.html">Haml tutorial</a></li></ul></li>
<li><a href="https://learnxinyminutes.com/docs/haml/">Learn Haml (basic)</a></li>
<li><a href="https://github.com/haml/haml">Haml</a> on <a href="/facts/GitHub/n1hNCsc3">GitHub</a></li>
<li><a href="http://phphaml.sourceforge.net/">phpHaml</a>, Haml implementation for <a href="/facts/PHP/vU6YRJX0">PHP</a></li>
<li><a href="https://groups.google.com/forum/?hl=en#!forum/haml">Haml Google Group</a></li>
<li><a href="http://weblog.rubyonrails.org/2007/1/19/haml-1-0">Haml 1.0</a>, announcement on the official Ruby on Rails weblog</li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>"Encoding". Retrieved 29 January 2016. <a href="http://haml.info/docs/yardoc/file.REFERENCE.html" target="_blank">http://haml.info/docs/yardoc/file.REFERENCE.html</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>"UTF encodings". GitHub. Retrieved 7 February 2016. <a href="https://github.com/haml/haml/blob/88110b0607efca433c13bb1e339dcb1131edf010/lib/haml/util.rb" target="_blank">https://github.com/haml/haml/blob/88110b0607efca433c13bb1e339dcb1131edf010/lib/haml/util.rb</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>"About". Retrieved 28 April 2018. <a href="http://haml.info/about.html" target="_blank">http://haml.info/about.html</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>"About". Retrieved 28 April 2018. <a href="http://haml.info/about.html" target="_blank">http://haml.info/about.html</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>"About". Retrieved 28 April 2018. <a href="http://haml.info/about.html" target="_blank">http://haml.info/about.html</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
<li id="fn:6"><p>"Changelog". GitHub. Retrieved 28 April 2018. <a href="https://github.com/haml/haml/blob/master/CHANGELOG.md" target="_blank">https://github.com/haml/haml/blob/master/CHANGELOG.md</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li>
<li id="fn:7"><p>"Changelog". GitHub. Retrieved 28 April 2018. <a href="https://github.com/haml/haml/blob/master/CHANGELOG.md" target="_blank">https://github.com/haml/haml/blob/master/CHANGELOG.md</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li>
<li id="fn:8"><p>"Changelog". GitHub. Retrieved 28 April 2018. <a href="https://github.com/haml/haml/blob/master/CHANGELOG.md" target="_blank">https://github.com/haml/haml/blob/master/CHANGELOG.md</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li>
<li id="fn:9"><p>"Trace Option in Haml". Retrieved 16 February 2016. <a href="http://www.rubydoc.info/github/haml/haml/Haml/Options:trace" target="_blank">http://www.rubydoc.info/github/haml/haml/Haml/Options:trace</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li>
<li id="fn:10"><p>"Using Haml". Retrieved 7 February 2016. <a href="http://haml.info/docs/yardoc/file.REFERENCE.html#using_haml" target="_blank">http://haml.info/docs/yardoc/file.REFERENCE.html#using_haml</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li>
</ol>

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Haml