class Phlex::HTML

def yield_content(&block)
	return unless block_given?
	original_length = @_target.length
	content = yield(self)
	unchanged = (original_length == @_target.length)
	if unchanged
		case content
		when String
			@_target << ERB::Util.html_escape(content)
		when Symbol
			@_target << ERB::Util.html_escape(content.name)
		when Integer, Float
			@_target << ERB::Util.html_escape(content.to_s)
		end
	end
	nil
end