Easily disable progress bar

[nschloe]

I'd like to dynamically disable the progress bar. Right now, I repeat lots of code like

if verbose {
    for entry in mylist.progress() {
        // ...
    }
} else {
    for entry in mylist {
        // ...
    }
}

There has to be a better way. Any hints?

[chris-laplante]

I don't think there's a built-in way, but you could write a trait that selectively swaps out the draw target. To hide the progress, you'd use ProgressDrawTarget::hidden.

[chris-laplante]

Untested, but something like this (this is for iter, rather than rayon):

trait ProgressMaybe
where
    Self: Sized,
{
    fn progress_if_not_verbose(self, is_verbose: bool) -> ProgressBarIter<Self>
    where
        Self: ExactSizeIterator,
    {
        let len = u64::try_from(self.len()).unwrap();
        let target = if is_verbose {
            ProgressDrawTarget::stderr()
        } else {
            ProgressDrawTarget::hidden()
        };

        let bar = ProgressBar::with_draw_target(Some(len), target);
        self.progress_with(bar)
    }
}

impl<S, T: Iterator<Item = S>> ProgressMaybe for T { }

[nschloe]

Perhaps this might work:

let pb = if verbose {
    ProgressBar::new(mylist.len() as u64)
} else {
    ProgressBar::hidden()
};