haml--haml/lib/sass/constant/funcall.rb

module Sass
  module Constant
    class Funcall
      attr_reader :name, :args

      def initialize(name, args)
        @name = name
        @args = args
      end

      def to_s
        perform.to_s
      end

      def inspect
        "#{name}(#{args.map {|a| a.inspect}.join(', ')})"
      end

      def perform
        unless Functions.public_instance_methods.include?(name) && name !~ /^__/
          return Constant::String.new("#{name}(#{args.join(', ')})")
        end

        return Functions.send(name, *args)
      rescue ArgumentError => e
        raise e unless e.backtrace.first =~ /:in `#{name}'$/
        raise Sass::SyntaxError.new("#{e.message} for `#{name}'")
      end
    end
  end
end