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feat: impl From<[(K, V); N]> for Map and Value #938

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6 changes: 6 additions & 0 deletions build.rs
Original file line number Diff line number Diff line change
@@ -32,6 +32,12 @@ fn main() {
println!("cargo:rustc-cfg=no_btreemap_remove_entry");
}

// Const generics
// https://blog.rust-lang.org/2021/03/25/Rust-1.51.0.html#const-generics-mvp
if minor < 51 {
println!("cargo:rustc-cfg=no_const_generics");
}

// BTreeMap::retain
// https://blog.rust-lang.org/2021/06/17/Rust-1.53.0.html#stabilized-apis
if minor < 53 {
9 changes: 9 additions & 0 deletions src/map.rs
Original file line number Diff line number Diff line change
@@ -430,6 +430,15 @@ impl<'de> de::Deserialize<'de> for Map<String, Value> {
}
}

#[cfg(not(no_const_generics))]
impl<const N: usize> From<[(String, Value); N]> for Map<String, Value> {
fn from(arr: [(String, Value); N]) -> Self {
// FromIterator::from_iter cannot be used before Rust 1.53
#[allow(deprecated)]
core::array::IntoIter::new(arr).collect()
}
}

impl FromIterator<(String, Value)> for Map<String, Value> {
fn from_iter<T>(iter: T) -> Self
where
19 changes: 19 additions & 0 deletions src/value/from.rs
Original file line number Diff line number Diff line change
@@ -233,6 +233,25 @@ impl<T: Into<Value>> FromIterator<T> for Value {
}
}

#[cfg(not(no_const_generics))]
impl<K: Into<String>, V: Into<Value>, const N: usize> From<[(K, V); N]> for Value {
/// Convert a list of map entry tuples to `Value`
///
/// # Examples
///
/// ```
/// use serde_json::Value;
///
/// let v = [("lorem", 40), ("ipsum", 2)];
/// let x: Value = v.into();
/// ```
fn from(arr: [(K, V); N]) -> Self {
// FromIterator::from_iter cannot be used before Rust 1.53
#[allow(deprecated)]
core::array::IntoIter::new(arr).collect()
}
}

impl<K: Into<String>, V: Into<Value>> FromIterator<(K, V)> for Value {
/// Convert an iteratable type to a `Value`
///