load_sass_variables.rb

# Throw this in config/initializers and add
# @import variables.sass to the top of application.sass
# to have all variables in app_config.yml
# available as variables in your sass stylesheets
# 
# First draft by unixmonkey (http://gist.github.com/323198)
# flatten method added by J. R. Schmid <jrs+git@weitnahbei.de>

app_config = YAML::load(File.open(File.join(RAILS_ROOT, 'config', 'app_config.yml')))

def flatten(input, prefix = nil)
  output = {}
  input.each do |key,value|
    if value.class == Hash
      output = output.merge(flatten(value, key)) 
    else
      output["#{prefix}_#{key}"] = value
    end
  end
  return output
end

sass_variables = []

flatten(app_config).each do |key,value|
  sass_variables << "!#{key}= #{value}"
end

File.open(File.join(RAILS_ROOT, 'public', 'stylesheets', 'sass', 'variables.sass'), 'w+') do |file|
  file.write(sass_variables.join("\n"))
end