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Add const examples to docs for field! #4

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Merged
nixonyh merged 1 commit into from
Oct 21, 2025
Merged

Add const examples to docs for field! #4

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44 changes: 22 additions & 22 deletions src/field.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -11,8 +11,6 @@
use core::any::TypeId;
use core::marker::PhantomData;

// use bevy_ecs::prelude::*;

/// A statically typed field path from a source type `S` to a target
/// type `T`.
///
Expand Down Expand Up @@ -137,22 +135,19 @@ impl<S, T> _FieldBuilder<S, T> {
/// age: u32,
/// }
///
/// let player_name: Field<Player, String> = field!(<Player>::name);
/// let player_age: Field<Player, u32> = field!(<Player>::age);
/// const PLAYER_NAME: Field<Player, String> = field!(<Player>::name);
/// let PLAYER_AGE: Field<Player, u32> = field!(<Player>::age);
///
/// assert_ne!(player_name.untyped(), player_age.untyped());
/// assert_ne!(PLAYER_NAME.untyped(), PLAYER_AGE.untyped());
/// ```
#[macro_export]
macro_rules! field {
(<$source:ty>$(::$field:tt)*) => {
{
let builder = $crate::field::_FieldBuilder::new(
|source: $source| source$(.$field)*,
$crate::stringify_field!($(::$field)*),
);

builder.build()
}
$crate::field::_FieldBuilder::new(
|source: $source| source$(.$field)*,
$crate::stringify_field!($(::$field)*),
)
.build()
};
}
pub use field;
Expand Down Expand Up @@ -282,14 +277,19 @@ mod tests {
}

#[test]
fn test_field() {
let field = field!(<Foo>);
assert_eq!(field.field_path, "");

let field = field!(<Foo>::0);
assert_eq!(field.field_path, stringify_field!(::0));

let field = field!(<NestedFoo>::inner::0);
assert_eq!(field.field_path, stringify_field!(::inner::0));
fn field_path_matches() {
const FIELD: Field<Foo, Foo> = field!(<Foo>);
assert_eq!(FIELD.field_path, "");

const FIELD_0: Field<Foo, u32> = field!(<Foo>::0);
assert_eq!(FIELD_0.field_path, stringify_field!(::0), "::0");

const FIELD_INNER_0: Field<NestedFoo, u32> =
field!(<NestedFoo>::inner::0);
assert_eq!(
FIELD_INNER_0.field_path,
stringify_field!(::inner::0),
"::inner::0"
);
}
}