Looks like you can't. I skimmed the TidyLib docs for the functions that configure its behaviour, but I don't see any calls to those in the HTML::Tidy sources. That really is a bummer. I was hoping to use the module to write a sane replacement for the annoying standalone tidy binary. It would also have been nice to be able to integrate TidyLib directly into a Perl-enabled Vim.

Makeshifts last the longest.