Filter for Haml files to convert %tag{:attr => "value"} into %tag(attr="value")

unhash.rb

#!/usr/bin/env ruby
# -*- coding: utf-8 -*-

# See: https://gist.github.com/1933369

# Filter for Haml files to convert %tag{:attr => "value"} into %tag(attr="value")

$tag_attr_order = {
  "link" => %w( rel sizes href ),
  "meta" => %w( name content )
}

def order tag, attributes
  new_attributes = []
  if attr_order = $tag_attr_order[tag]
    new_attributes = attr_order.select{|n| attributes.has_key? n}.map{|n| attributes.delete(n)}
  end
  new_attributes + attributes.values
end

hash_re = /\s*(?::(\w+)\s*=>|(\w+):)\s*(\".*?\"|'.*?')\s*,?\s*/
tag_re = /%(\w+)(.*?)\{((?:#{hash_re})*)\}/
print ARGF.read.gsub(tag_re) {
  tag = $1
  selectors = $2
  attributes = {}
  $3.scan hash_re do |key, key2, value|
    key ||= key2
    attributes[key] = "#{key}=#{value}"
  end
  attributes = order tag, attributes
  "%#{tag}#{selectors}(#{attributes.join " "})"
}