Trait iter_scan::IterScan

pub trait IterScan: Iterator + Sized {
    fn scan_clone<Compute, State>(
        self,
        initial: State,
        compute: Compute
    ) -> Scan<Self, fn(_: State) -> (State, State), Compute, State> 
    where
        State: Clone,
        Compute: FnMut(State, Self::Item) -> State,
    { ... }
    fn scan_copy<Compute, State>(
        self,
        initial: State,
        compute: Compute
    ) -> Scan<Self, fn(_: State) -> (State, State), Compute, State> 
    where
        State: Copy,
        Compute: FnMut(State, Self::Item) -> State,
    { ... }
    fn scan_with_tuple<Compute, State>(
        self,
        initial: State,
        compute: Compute
    ) -> Scan<Self, fn(_: (State, State)) -> (State, State), Compute, State> 
    where
        Compute: FnMut(State, Self::Item) -> (State, State),
    { ... }
}

Iterator scan methods that don’t suck.

Provided Methods

fn scan_clone<Compute, State>(
    self,
    initial: State,
    compute: Compute
) -> Scan<Self, fn(_: State) -> (State, State), Compute, State> where
    State: Clone,
    Compute: FnMut(State, Self::Item) -> State,

This iterator adapter holds an internal state and emit this state on each iteration.

This internal state can be cloned.

scan_clone() takes 2 arguments:

• An initial value which seeds the internal state.
• A closure that:
  • Takes 2 arguments: Copy of the internal state from the previous iteration and the current item.
  • Returns the new state for the next iteration.

Example: Basic usage

use iter_scan::IterScan;
let input = ['a', 'b', 'c', 'd', 'e', 'f'];
let output: Vec<_> = input
    .into_iter()
    .scan_clone(String::new(), |acc, x| format!("{acc}{x}"))
    .collect();
assert_eq!(output, ["a", "ab", "abc", "abcd", "abcde", "abcdef"]);

fn scan_copy<Compute, State>(
    self,
    initial: State,
    compute: Compute
) -> Scan<Self, fn(_: State) -> (State, State), Compute, State> where
    State: Copy,
    Compute: FnMut(State, Self::Item) -> State,

This iterator adapter holds an internal state and emit this state on each iteration.

This internal state can be copied.

scan_copy() takes 2 arguments:

• An initial value which seeds the internal state.
• A closure that:
  • Takes 2 arguments: Copy of the internal state from the previous iteration and the current item.
  • Returns the new state for the next iteration.

Example: Basic usage

use iter_scan::IterScan;
let input = [2, 3, 4, 5];
let output: Vec<u64> = input
    .into_iter()
    .scan_copy(1, |acc, x| acc * x)
    .collect();
assert_eq!(output, [2, 6, 24, 120]);

fn scan_with_tuple<Compute, State>(
    self,
    initial: State,
    compute: Compute
) -> Scan<Self, fn(_: (State, State)) -> (State, State), Compute, State> where
    Compute: FnMut(State, Self::Item) -> (State, State),

This iterator adapter holds an internal state and emit this state on each iteration.

This adapter should be used when the internal state can neither be cloned nor copied.

scan_with_tuple() takes 2 arguments:

• An initial value which seeds the internal state.
• A closure that:
  • Takes 2 arguments: Copy of the internal state from the previous iteration and the current item.
  • Returns a tuple of the new state and its identical copy.

Implementors

impl<X: Iterator + Sized> IterScan for X