Trait FallibleIteratorMut

Source

pub trait FallibleIteratorMut {
    type Item;
    type Error;

    // Required method
    fn next(&mut self) -> Result<Option<&mut Self::Item>, Self::Error>;

    // Provided methods
    fn size_hint(&self) -> (usize, Option<usize>) { ... }
    fn map<F, B>(&mut self, f: F) -> Map<'_, Self, F>
       where Self: Sized,
             F: FnMut(&mut Self::Item) -> Result<B, Self::Error> { ... }
}

Expand description

Provides a FallibleIterator over mutable references.

Ordinarily a FallibleIterator iterates over owned items, which makes this trait incompatible with it. The map method allows converting this trait into a FallibleIterator, and it’s also possible to use with a while let loop:

use sqlite3_ext::FallibleIteratorMut;

fn dump<I: FallibleIteratorMut>(mut it: I) -> Result<(), I::Error>
where
    I::Item: std::fmt::Debug,
{
    while let Some(x) = it.next()? {
        println!("{:?}", x);
    }
    Ok(())
}