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Add retain to Map #822

Merged
merged 9 commits into from
Nov 13, 2021
Merged

Add retain to Map #822

merged 9 commits into from
Nov 13, 2021

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deankarn
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@deankarn deankarn commented Nov 12, 2021

This adds the retain function to the Map type which calls the inner
maps, Either indexmap or std BTreeMap's, retain.

I'm trying to mutate a Value::Object's Map in-place and could't find a
nice way without the retain function.

These new retain functions will also only be included when compiling with Rust 1.53.0+ when retain was added to the BTreeMap in the std lib https://blog.rust-lang.org/2021/06/17/Rust-1.53.0.html#stabilized-apis

Dean Karn added 6 commits November 11, 2021 20:24
This adds the `retain` function to the Map type which calls the inner
maps, Either indexmap or std BTreeMap's, retain.

I'm trying to mutate a Value::Object's Map in-place and could't find a
nice way without the retain function.
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Thanks!

build.rs Outdated Show resolved Hide resolved
src/map.rs Outdated
Comment on lines 237 to 261
#[cfg(all(feature = "preserve_order", not(no_btreemap_retain)))]
/// Retains only the elements specified by the predicate.
///
/// In other words, remove all pairs `(k, v)` such that `f(&k, &mut v)` returns `false`.
/// The elements are visited in ascending key order.
#[inline]
pub fn retain<F>(&mut self, f: F)
where
F: FnMut(&String, &mut Value) -> bool,
{
self.map.retain(f);
}

#[cfg(all(not(feature = "preserve_order"), not(no_btreemap_retain)))]
/// Retains only the elements specified by the predicate.
///
/// In other words, remove all pairs `(k, v)` such that `f(&k, &mut v)` returns `false`.
/// The elements are visited in ascending key order.
#[inline]
pub fn retain<F>(&mut self, f: F)
where
F: FnMut(&String, &mut Value) -> bool,
{
self.map.retain(f);
}
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Why are there two identical copies of this function? (Maybe I'm not observant enough to notice the difference — what is the difference between these?)

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Thanks for catching my mistake @dtolnay

They were originally different but eventually became the same. Combination of late night coding and distraction of kids. It should be good to go now.

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Looks good!

@dtolnay dtolnay merged commit 37da27f into serde-rs:master Nov 13, 2021
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dtolnay commented Nov 13, 2021

Published in 1.0.70.

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2 participants