[parenscript-devel] help: question about eval-when usage

I am reading codes of paren-util. I find that it use "eval-when" inside defpsmacro. But I don't find that parenscript reference says eva-when is supported. As I understand, defpsmacro should expand into a valid parenscript code. Does parenscript support eval-when that although doesn't appear in reference. Thanks.