Derive Macro Delta 

#[derive(Delta)]
{
    // Attributes available to this derive:
    #[delta_struct]
}

Derives Delta, generating a {Self}Delta struct that holds only the changed parts of a value plus the trait implementation that produces and applies one.

The generated struct takes the visibility and generic parameters of the type it is derived on, and all of its fields are pub. See the delta-struct crate documentation for the full picture, including trait bounds, serde usage, and limitations; what follows is the attribute reference.

Container attributes

Attribute	Effect
default = "<field type>"	Field type for fields that don’t specify one. Defaults to "scalar".
delta_leader = "<tokens>"	Tokens emitted directly above the generated struct — derives, doc comments, anything.

Field attributes

Attribute	Effect
field_type = "<field type>"	How this field is diffed. Overrides the container’s default.
delta_leader = "<tokens>"	Tokens emitted directly above the generated field. On an unordered field they land above both the _add and the _remove field.

Field types

Value	Delta representation	Requires
"scalar"	Option<T>	T: PartialEq
"unordered"	{field}_add and {field}_remove, both Vec<Item>	T: IntoIterator + FromIterator<Item> + Extend<Item>, Item: PartialEq
"ordered"	SeqDelta<Item>, a Myers edit script	T: IntoIterator + FromIterator<Item>, Item: Hash + Eq
"delta"	Option<<T as Delta>::Output>	T: Delta

Example

use delta_struct::Delta;

#[derive(Delta)]
#[delta_struct(delta_leader = "#[derive(Debug)]")]
struct Device {
    #[delta_struct(field_type = "unordered")]
    services: Vec<String>,
    online: bool,
}

The example is not run as a doctest because this crate cannot depend on the crate that re-exports it; the tested versions live in the delta-struct crate documentation.