add_class

# provides a slick way to add classes inside haml attribute collections
# 
# examples:
#   %div{add_class("current")} 
#   #=> adds the "current" class to the div
#   
#   %div{add_class("current", :if => current?)} 
#   #=> adds the "current" class to the div if current? method 
#
#   %div{add_class("highlight", :unless => logged_in?)} 
#   #=> adds the "highlight" class to the div unless logged_in? method returns true
def add_class(css_class, options = {})
 return {} unless css_class
  
  if options.has_key?(:unless) && !options[:unless]
    return {:class => css_class}
  end
  
  if options.has_key?(:if) && options[:if]
    return {:class => css_class}
  end
  
  if !options.has_key?(:if) and !options.has_key?(:unless)
    {:class => css_class}
  else
    {}
  end
end

funky_haml_attribute_helper.rb

# Adding haml attributes
# 
# trueish = true
# 
# FunkyHamlAttributeHelper.add_class('content')         # => {:class => "content"}
# FunkyHamlAttributeHelper.add_id('content')            # => {:id => "content"}
# FunkyHamlAttributeHelper.add_flux_capacitor('future') # => {:flux_capacitor => "future"}
# 
# FunkyHamlAttributeHelper.add_class('content', :if => trueish)     # {:class => "content"}
# FunkyHamlAttributeHelper.add_class('content', :unless => trueish) # {}
# 
# FunkyHamlAttributeHelper.add_('content') # => {}
module FunkyHamlAttributeHelper
  def self.method_missing(method, *args)
    return {} if args.empty?
    
    if method =~ /^add_(\S+)/
      property = $1.to_sym
      value = args[0]
      options = args[1] ||= {}
      
      if options.has_key?(:unless) && !options[:unless]
        return {property => value}
      end
      
      if options.has_key?(:if) && options[:if]
        return {property => value}
      end
      
      if !options.has_key?(:if) and !options.has_key?(:unless)
        return {property => value}
      end
      
      return {}
    else
      return {}
    end
  end
end

haml_attribute_helper.rb

# Adding haml attributes
# 
# HamlAttributeHelper.add(:class, 'content')         # => {:class => "content"}
# HamlAttributeHelper.add(:id, 'content')            # => {:id => "content"}
# HamlAttributeHelper.add(:flux_capacitor, 'future') # => {:flux_capacitor => "future"}
# 
# HamlAttributeHelper.add(:class, 'content', :if => trueish)     # {:class => "content"}
# HamlAttributeHelper.add(:class, 'content', :unless => trueish) # {}
module HamlAttributeHelper
  def self.add(property, value, options = {})
    return {} unless property || value
    
    if options.has_key?(:unless) && !options[:unless]
      return {property => value}
    end
    
    if options.has_key?(:if) && options[:if]
      return {property => value}
    end
    
    if !options.has_key?(:if) and !options.has_key?(:unless)
      return {property => value}
    end
    
    return {}
  end
end