feature request: Convert file to file

[DcsMarionDickten]

How about something like

def Pandoc.convert_file(inputfile, outputfile, *kwargs, **options)
    # use it like Pandoc.convert_file(myinputfile.md, myoutputfile.pdf, '--pdf-engine pdfroff', from: 'markdown')
    target = options[:to].present? ? options[:to] : outputfile.split('.')[-1] # only needed if file extension != name of output type
    source = options[:from].present? ? options[:from] : inputfile.split('.')[-1] # only needed if file extension != name of input type
    if kwargs.empty?
      return PandocRuby.new([inputfile], '-s', options, from: source, o: outputfile).send("to_#{target}")
    elsif options.empty?
      PandocRuby.new([inputfile], kwargs, '-s', from: source, o: outputfile).send("to_#{target}")
    else
      PandocRuby.new([inputfile], kwargs, '-s', options, from: source, o: outputfile).send("to_#{target}")
    end
  end

to directly convert from file to file without the kwargs (as far as that is possible)? This code is very elementary and probably won't work in many cases, but it's the first thing I wrote to integrate PandocRuby better with my code.