method init : unit = (
Checkbutton.configure types ~command:(fun () -> (if typesString="" then typesString <- " --types " else typesString <- ""));
Checkbutton.configure inits ~command:(fun () -> (if initString="" then initString <- " --init " else initString <- ""));
Checkbutton.configure rules ~command:(fun () -> (if rulesString="" then rulesString <- " --rules " else rulesString <- ""));
Checkbutton.configure goals ~command:(fun () -> (if goalsString="" then goalsString <- " --goals " else goalsString <- ""));
pack ~side:`Top [optionFrame];
pack ~side:`Top [optionLabel];
pack ~side:`Top [types];
pack ~side:`Top [inits];
pack ~side:`Top [rules];
pack ~side:`Top [goals];)