Re: [PATCH 2/5] rust: time: Introduce Duration type

[Boqun Feng]

On Tue, Mar 26, 2024 at 10:11:07AM -0700, Boqun Feng wrote:
[...]
> > > +impl Duration {
> > > +    /// Creates a new duration of `ns` nanoseconds.
> > > +    pub const fn new(ns: i64) -> Self {
> > > +        Self { inner: ns }
> > > +    }
> > > +
> > > +    /// Divides the number of nanoseconds by a compile-time constant.
> > > +    #[inline]
> > > +    fn divns_constant<const DIV: i64>(self) -> i64 {
> > > +        self.to_ns() / DIV
> > > +    }
> > 
> > I am a bit confused, why is this better than writing
> > `self.to_ns() / DIV` at the callsite?
> > 
> 
> Hmm.. you're right, there should be no difference I think. If there is
> nothing I'm missing from Alice, I will drop this function in the next
> version.
> 

On a second thought, I think this prevents accidentally divide a
non-const value, in other words, if you use this function, you're
guaranteed the divisor is a constant, and you have the compiler checking
that for you. So in that sense, I think it makes sense to remain it
here. Thoughts?

Regards,
Boqun

> Regards,
> Boqun
> 
> > -- 
> > Cheers,
> > Benno
> > 
> > > +
> > > +    /// Returns the number of milliseconds.
> > > +    #[inline]
> > > +    pub fn to_ms(self) -> i64 {
> > > +        self.divns_constant::<NSEC_PER_MSEC>()
> > > +    }
> > > +
> > > +    /// Returns the number of nanoseconds.
> > > +    #[inline]
> > > +    pub fn to_ns(self) -> i64 {
> > > +        self.inner
> > > +    }
> > > +}
> > > --
> > > 2.44.0
> > >