40 lines
1.7 KiB
Rust
40 lines
1.7 KiB
Rust
#![feature(iterator_for_each)]
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use std::iter::repeat;
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#[allow(trivially_copy_pass_by_ref)]
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fn square_is_lower_64(x: &u32) -> bool { x * x < 64 }
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#[allow(maybe_infinite_iter)]
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#[deny(infinite_iter)]
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fn infinite_iters() {
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repeat(0_u8).collect::<Vec<_>>(); // infinite iter
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(0..8_u32).take_while(square_is_lower_64).cycle().count(); // infinite iter
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(0..8_u64).chain(0..).max(); // infinite iter
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(0_usize..).chain([0usize, 1, 2].iter().cloned()).skip_while(|x| *x != 42).min(); // infinite iter
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(0..8_u32).rev().cycle().map(|x| x + 1_u32).for_each(|x| println!("{}", x)); // infinite iter
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(0..3_u32).flat_map(|x| x..).sum::<u32>(); // infinite iter
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(0_usize..).flat_map(|x| 0..x).product::<usize>(); // infinite iter
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(0_u64..).filter(|x| x % 2 == 0).last(); // infinite iter
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(0..42_u64).by_ref().last(); // not an infinite, because ranges are double-ended
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(0..).next(); // iterator is not exhausted
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}
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#[deny(maybe_infinite_iter)]
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fn potential_infinite_iters() {
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(0..).zip((0..).take_while(square_is_lower_64)).count(); // maybe infinite iter
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repeat(42).take_while(|x| *x == 42).chain(0..42).max(); // maybe infinite iter
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(1..).scan(0, |state, x| { *state += x; Some(*state) }).min(); // maybe infinite iter
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(0..).find(|x| *x == 24); // maybe infinite iter
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(0..).position(|x| x == 24); // maybe infinite iter
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(0..).any(|x| x == 24); // maybe infinite iter
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(0..).all(|x| x == 24); // maybe infinite iter
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(0..).zip(0..42).take_while(|&(x, _)| x != 42).count(); // not infinite
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repeat(42).take_while(|x| *x == 42).next(); // iterator is not exhausted
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}
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fn main() {
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infinite_iters();
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potential_infinite_iters();
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}
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