use std::ops::{
RangeFull,
RangeFrom,
RangeTo,
Range,
};
pub trait IndexRange<T=usize> {
#[inline]
fn start(&self) -> Option<T> { None }
#[inline]
fn end(&self) -> Option<T> { None }
}
impl<T> IndexRange<T> for RangeFull {}
impl<T: Copy> IndexRange<T> for RangeFrom<T> {
#[inline]
fn start(&self) -> Option<T> { Some(self.start) }
}
impl<T: Copy> IndexRange<T> for RangeTo<T> {
#[inline]
fn end(&self) -> Option<T> { Some(self.end) }
}
impl<T: Copy> IndexRange<T> for Range<T> {
#[inline]
fn start(&self) -> Option<T> { Some(self.start) }
#[inline]
fn end(&self) -> Option<T> { Some(self.end) }
}