Macro impl_derived_property 

macro_rules! impl_derived_property {
    (
            $name:ident,
            $entity:ident,
            [$($dependency:ident),*]
            $(, [$($global_dependency:ident),*])?,
            |$($param:ident),+| $derive_fn:expr
            $(, $($extra:tt)+)*
        ) => { ... };
    (
            @construct_compute_fn
            $entity:ident,
            [$($dependency:ident),*],
            [$($global_dependency:ident),*],
            |$($param:ident),+| $derive_fn:expr
        ) => { ... };
}

Implements the Property trait for an existing type as a derived property.

Accepts the same parameters as define_derived_property!, except the first parameter is the name of a type assumed to already be declared rather than a type declaration. This is the derived property equivalent of impl_property!. It calls impl_property! with the appropriate derived property parameters.