use syntax::ext::base; use syntax::print; use syntax::tokenstream; use syntax_pos; pub fn expand_syntax_ext<'cx>(_cx: &'cx mut base::ExtCtxt<'_>, sp: syntax_pos::Span, tts: &[tokenstream::TokenTree]) -> Box { println!("{}", print::pprust::tts_to_string(tts)); // any so that `log_syntax` can be invoked as an expression and item. base::DummyResult::any_valid(sp) }