let options = [
"-i", Arg.String (fun s -> ic := open_in s), "<file>\tread from <file> instead of standard input";
"-o", Arg.String (fun s -> oc := open_out s), "<file>\toutput to <file> instead of standard output";
"--page", Arg.Set gen_page, " generate a whole page instead of just a piece of html";
"--css", Arg.Set_string css_style, "<url>\tcss style sheet to use, when generating a whole page (default: "^ !css_style ^")";
"--gen-css", Arg.String (fun s -> gen_css := Some s),
"<file>\tgenerate a default CSS style sheet in given file";
]