Struct FnSource 

pub struct FnSource<F, T, E> { /* private fields */ }

Source adapter over a closure that produces fallible items.

The closure returns Ok(Some(item)) to emit, Ok(None) to signal end-of-stream, or Err(E) to raise a source error.

Example

use pipe_io::source::{FnSource, Source};

let mut n = 0u32;
let mut s = FnSource::new(move || -> Result<Option<u32>, &'static str> {
    n += 1;
    if n <= 3 { Ok(Some(n)) } else { Ok(None) }
});

assert_eq!(s.pull().unwrap(), Some(1));
assert_eq!(s.pull().unwrap(), Some(2));
assert_eq!(s.pull().unwrap(), Some(3));
assert_eq!(s.pull().unwrap(), None);

Implementations

impl<F, T, E> FnSource<F, T, E>

where F: FnMut() -> Result<Option<T>, E>,

pub fn new(func: F) -> Self

Wrap a closure into a source.

Trait Implementations

impl<F, T, E> Source for FnSource<F, T, E>

where F: FnMut() -> Result<Option<T>, E>, E: StageError,

type Item = T

Type of item produced.

type Error = E

Error type the source can return.

fn pull(&mut self) -> Result<Option<Self::Item>, Self::Error>

Pull the next item.

fn close(&mut self) -> Result<(), Self::Error>

Close the source. Default impl does nothing.