pub trait TkXView<Inst: TkInstance>{
// Provided methods
fn xview(&self) -> Result<(c_double, c_double), Enum2<DeError, InterpError>> { ... }
fn xview_moveto(&self, fraction: c_double) -> InterpResult<()> { ... }
fn xview_scroll_units(&self, number: c_double) -> InterpResult<()> { ... }
fn xview_scroll_pages(&self, number: c_double) -> InterpResult<()> { ... }
fn xview_(&self, args: Vec<Obj>) -> InterpResult<()> { ... }
}