d2_iterators_in_rust 0.1.0

D2 Iterators
Documentation 
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mod gen_range;
mod combi;
mod v4_intoiter;
use std::ops::AddAssign;

pub trait Rangeable: AddAssign + PartialOrd + Copy {}

impl<T: AddAssign + PartialOrd + Copy> Rangeable for T {}

pub struct GenRangeIterator<T: Rangeable> {
    curr: T,
    stop: T,
    step: T,
}

impl<T: Rangeable> GenRangeIterator<T> {
    pub fn new(start: T, stop: T, step: T) -> Self {
        GenRangeIterator { curr: start, stop, step }
    }
}

impl<T: Rangeable> Iterator for GenRangeIterator<T> {
    type Item = T;
    fn next(&mut self) -> Option<Self::Item> {
        if self.curr >= self.stop {
            return None;
        }
        let res = self.curr;
        self.curr += self.step;
        Some(res)
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn gen_test() {
        let mut m = 0;
        let it = GenRangeIterator::new(5, 12, 3);
        for s in it {
            m += s;
        }

        assert_eq!(m, 5 + 8 + 11);
    }

    #[test]
    fn filter() {
        let v: i32 = GenRangeIterator::new(3, 13, 3)
            .filter(|x| x % 2 == 0)
            .sum();
        assert_eq!(v, 6 + 12)
    }
}