Function syntax::print::pprust::print_crate

pub fn print_crate<'a>(
    cm: &'a SourceMap, 
    sess: &ParseSess, 
    krate: &Crate, 
    filename: FileName, 
    input: &mut dyn Read, 
    out: Box<dyn Write + 'a>, 
    ann: &'a dyn PpAnn, 
    is_expanded: bool
) -> Result<()>

Requires you to pass an input filename and reader so that it can scan the input text for comments to copy forward.