1#[cfg(feature = "fold")] 2pub(crate) mod fold { 3 use crate::punctuated::{Pair, Punctuated}; 4 5 pub(crate) trait FoldHelper { 6 type Item; 7 fn lift<F>(self, f: F) -> Self 8 where 9 F: FnMut(Self::Item) -> Self::Item; 10 } 11 12 impl<T> FoldHelper for Vec<T> { 13 type Item = T; 14 fn lift<F>(self, f: F) -> Self 15 where 16 F: FnMut(Self::Item) -> Self::Item, 17 { 18 self.into_iter().map(f).collect() 19 } 20 } 21 22 impl<T, U> FoldHelper for Punctuated<T, U> { 23 type Item = T; 24 fn lift<F>(self, mut f: F) -> Self 25 where 26 F: FnMut(Self::Item) -> Self::Item, 27 { 28 self.into_pairs() 29 .map(Pair::into_tuple) 30 .map(|(t, u)| Pair::new(f(t), u)) 31 .collect() 32 } 33 } 34} 35