ruby_css.rb

# Ruby-CSS - Stylesheets in Ruby code
#
# Usage: ruby ruby_css.rb <somefile.rcss>
# See test.rcss for example.
#
# Worst DSL EVER for stylesheets! DO NOT USE THIS AT WORK! ;-)

class Selector

  attr_accessor :name, :properties, :children
  
  def initialize(name, &blk)
    @properties = {}
    @name       = name.to_s
    @children   = []
    instance_eval(&blk)
  end
  
  # Generates CSS for the given selector name.
  #
  # Example:
  #   s('h1.title') { font_size '2em' }
  #
  # Generates:
  #   h1.title {
  #     font-size: 2em;
  #   }
  #
  def s(selector_name, &blk)
    @children << Selector.new("#{@name} #{selector_name}", &blk)
  end
  
  # Generates CSS for a given ID.
  #
  # Example:
  #   id('posts') { font_size '12px' }
  #
  # Generates:
  #   #posts {
  #     font-size: 12px;
  #   }
  #
  def id(id_name, &blk)
    @children << Selector.new("#{@name} \##{id_name}", &blk)
  end
  
  # Generates CSS for a given class name.
  #
  # Example:
  #   c('post') { font_size '12px' }
  #
  # Generates:
  #   .post {
  #     font-size: 12px;
  #   }
  #
  def c(id_name, &blk)
    @children << Selector.new("#{@name} .#{id_name}", &blk)
  end
  
  # Handles generation of CSS for any HTML tag.
  #
  # Example:
  #   nav { float 'right' }
  #
  # Generates:
  #   nav {
  #     float: right;
  #   }
  #
  # TODO: Create selectors only for valid HTML tags.
  #
  def method_missing(method_name, *args, &blk)
    if block_given?
      @children << Selector.new([@name, method_name].join(' '), &blk)
    else
      @properties[method_name.to_s.sub('_', '-')] = args[0]
    end
  end
  
  # Generates the formatted output CSS as a string.
  #
  def to_s
    css = "#{@name} {\n"
    @properties.each_pair { |k, v| css += "  #{k}: #{v};\n" }
    css += "}\n\n"
    @children.each { |c| css += c.to_s }
    css
  end
  
end

class Stylesheet

  def initialize(file)
    @__selectors = []
    instance_eval( File.read(file) )
  end
  
  def method_missing(method_name, *args, &blk)
    @__selectors << Selector.new(method_name, &blk) if block_given?
  end
  
  def to_css
    puts "\n\n"
    @__selectors.each do |s|
      puts s.to_s
    end
  end
  
end

Stylesheet.new(ARGV[0]).to_css if ARGV.length > 0

test.rscc

# This RCSS file is simply Ruby code pretending to be CSS, so you can use 
# variables like the on below. These two lines will be ignored as comment.

$greyish_color = '#E9E9E9'

# We start our Ruby-CSS here. For the CSS properties

body {                                           #=> body { font-fam... }
  font_family 'Arial, Verdana, sans-serif'       #=>   font-family: Arial, V...
  
  header {                                       #=> body header { width: ... }
    width '960px'
    
    nav           { float 'right' }              #=> body header nav { flo... }
    s('h1.title') { font_size '12px' }           #=> body header nav h1.title {
  }

  id('posts') {                                  #=> body #posts { ... }
    font_size '12px'                             #=>   font-size: 12px;
    
    c('post') { color $greyish_color }           #=> body #posts .post { ... }
  }
}

a {                                              #=> a { ... }
  text_decoration 'none'                         #=>    text-decoration: none;
}