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use std::mem::replace;
use crate::{Span, DUMMY_SP};
pub trait Take: Sized {
fn take(&mut self) -> Self {
replace(self, Self::dummy())
}
fn dummy() -> Self;
#[inline]
fn map_with_mut<F>(&mut self, op: F)
where
F: FnOnce(Self) -> Self,
{
let dummy = Self::dummy();
let cur_val = replace(self, dummy);
let new_val = op(cur_val);
let _dummy = replace(self, new_val);
}
}
impl<T> Take for Option<T> {
fn dummy() -> Self {
None
}
}
impl<T> Take for Box<T>
where
T: Take,
{
fn dummy() -> Self {
Box::new(T::dummy())
}
}
impl<T> Take for Vec<T> {
fn dummy() -> Self {
vec![]
}
}
impl Take for Span {
fn dummy() -> Self {
DUMMY_SP
}
}