## 4.0.0
* The Haml exectutable now accepts an `--autoclose` option. You can now
specify a list of tags that should be autoclosed
* The `:ruby` filter no longer redirects $stdout to the Haml document, as this
is not thread safe. Instead it provides a `haml_io` local variable, which is
an IO object that writes to the document.
* HTML5 is now the default output format rather than XHTML. This was already
the default on Rails 3+, so many users will notice no difference.
* The :sass filter now wraps its output in a script tag, as do the new :less and
:scss filters. The :coffee filter wraps its output in a script tag.
* Haml now supports only Rails 3 and above, and Ruby 1.8.7 and above. If you
still need support for Rails 2 and Ruby 1.8.6, please use Haml 3.1.x which
will continue to be maintained for bug fixes.
* The :javascript and :css filters no longer add CDATA tags when the format is
html4 or html5. This can be overridden by setting the `cdata` option to
`true`. CDATA tags are always added when the format is xhtml.
* HTML2Haml has been extracted to a separate gem, creatively named "html2haml".
* The `:erb` filter now uses Rails's safe output buffer to provide XSS safety.
* Haml's internals have been refactored to move the parser, compiler and options
handling into independent classes, rather than including them all in the
Engine module. You can also specify your own custom Haml parser or compiler
class in Haml::Options in order to extend or modify Haml reasonably easily.
* Add an {file:REFERENCE.md#hyphenate_data_attrs-option `:hyphenate_data_attrs`
option} that converts underscores to hyphens in your HTML5 data keys. This is
a language change from 3.1 and is enabled by default.
(thanks to [Andrew Smith](https://github.com/fullsailor))
* All Hash attribute values are now treated as HTML5 data, regardless of key.
Previously only the "data" key was treated this way. Allowing arbitrary keys
means you can now easily use this feauture for Aria attributes, among other
uses.
(thanks to [Elvin Efendi](https://github.com/ElvinEfendi))
* Added `remove_whitespace` option to always remove all whitespace around Haml
tags. (thanks to [Tim van der Horst](https://github.com/vdh))
* Haml now flattens deeply nested data attribute hashes. For example:
`.foo{:data => {:a => "b", :c => {:d => "e", :f => "g"}}}`
would render to:
`<div class='foo' data-a='b' data-c-d='e' data-c-f='g'></div>`
(thanks to [Péter Pál Koszta](https://github.com/koszta))
* Filters that rely on third-party template engines are now implemented using
[Tilt](github.com/rtomayko/tilt). Several new filters have been added, namely
SCSS (:scss), LessCSS, (:less), and Coffeescript (:coffee/:coffeescript).
Though the list of "official" filters is kept intentionally small, Haml comes
with a helper method that makes adding support for other Tilt-based template
engines trivial.
As of 4.0, Haml will also ship with a "haml-contrib" gem that includes useful
but less-frequently used filters and helpers. This includes several additional
filters such as Nokogiri, Yajl, Markaby, and others.
* Generate object references based on `#to_key` if it exists in preference to
`#id`.
* Performance improvements.
(thanks to [Chris Heald](https://github.com/cheald))
* Helper `list_of` takes an extra argument that is rendered into list item
attributes.
(thanks [Iain Barnett](http://iainbarnett.me.uk/))
* Fix parser to allow lines ending with `some_method?` to be a Ruby multinline.
(thanks to [Brad Ediger](https://github.com/bradediger))
* Always use :xhtml format when the mime_type of the rendered template is
'text/xml'.
(thanks to [Stephen Bannasch](https://github.com/stepheneb))
* html2haml now includes an `--html-attributes` option.
(thanks [Stefan Natchev](https://github.com/snatchev))
* Fix for inner whitespace removal in loops.
(thanks [Richard Michael](https://github.com/richardkmichael))
* Use numeric character references rather than HTML entities when escaping
double quotes and apostrophes in attributes. This works around some bugs in
Internet Explorer earlier than version 9.
(thanks [Doug Mayer](https://github.com/doxavore))
* Fix multiline silent comments: Haml previously did not allow free indentation
inside multline silent comments.
* Fix ordering bug with partial layouts on Rails.
(thanks [Sam Pohlenz](https://github.com/spohlenz))
* Add command-line option to suppress script evaluation.
* It's now possible to use Rails's asset helpers inside the Sass and SCSS
filters. Note that to do so, you must make sure sass-rails is loaded in
production, usually by moving it out of the assets gem group.
* The Haml project now uses [semantic versioning](http://semver.org/).
## 3.2.0
The Haml 3.2 series was released only as far as 3.2.0.rc.4, but then was
renamed to Haml 4.0 when the project adopted semantic versioning.
## 3.1.8
* Fix for line numbers reported from exceptions in nested blocks
(thanks to Grant Hutchins & Sabrina Staedt).
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