let guess_format t l =
match Filename.basename(Sys.argv.(0)) with
|"debcheck"|"dose-debcheck" -> (Url.Deb, true)
|"eclipsecheck"|"dose-eclipsecheck" -> (Url.Eclipse, true)
|"rpmcheck"|"dose-rpmcheck" -> (Url.Synthesis,true)
|_ when OptParse.Opt.is_set t ->
(Url.scheme_of_string (OptParse.Opt.get t),true)
|_ -> (Input.guess_format [l], false)