class Phlex::SGML

def capture(&block)
	return "" unless block_given?
	original_buffer_content = @_target.dup
	@_target.clear
	begin
		yield_content(&block)
		new_buffer_content = @_target.dup
	ensure
		@_target.clear
		@_target << original_buffer_content
	end
	new_buffer_content
end