use tk::*;
use tk::cmd::*;
fn main() -> TkResult<()> {
let tk = make_tk!()?;
let root = tk.root();
let check = root
.add_ttk_checkbutton( "check" -text("Use Metric") -command( "metricChanged" )
-variable("measuresystem") -onvalue("metric") -offvalue("imperial") )?
.pack(())?;
assert!( check.instate( TtkState::Alternate )? );
Ok( main_loop() )
}