def parse_sass_file(file, options = {})
      Sass::Engine.for_file(file, options).to_tree.children.each do |node|
        if node.kind_of? Sass::Tree::VariableNode
          if node.expr.is_a? Sass::Script::Color
            add_color(node)

          elsif node.expr.is_a? Sass::Script::Funcall # if function call (e.g. lighten(#000, 20%)), try to resolve to color
            resolved = node.expr.perform(sass_env) rescue false

            if resolved.is_a? Sass::Script::Color
              add_color(node, resolved.to_s)
            end

          elsif node.expr.is_a? Sass::Script::Variable
            (self.variable_mappings[node.expr.name] ||= []) << node.name # add to variable mapping
          end

        end
      end
    end
def parse_sass_file(file, options = {})
      Sass::Engine.for_file(file, options).to_tree.children.each do |node|
        if node.kind_of? Sass::Tree::VariableNode
          if node.expr.is_a? Sass::Script::Color
            add_color(node)

          elsif node.expr.is_a? Sass::Script::Funcall # if function call (e.g. lighten(#000, 20%)), try to resolve to color
            resolved = node.expr.perform(sass_env) rescue false

            if resolved.is_a? Sass::Script::Color
              add_color(node, resolved.to_s)
            end

          elsif node.expr.is_a? Sass::Script::Variable
            (self.variable_mappings[node.expr.name] ||= []) << node.name # add to variable mapping
          end

        end
      end
    end
parses Sass file and returns hash with colors and variable_mappings (or false)