macro_rules! lens { ($ty:ty, [$index:expr]) => { ... }; ($ty:ty, $($field:tt)*) => { ... }; }
Expand description
Construct a lens accessing a type’s field
This is a convenience macro for constructing Field
lenses for fields or indexable elements.
struct Foo { x: Bar }
struct Bar { y: [i32; 10] }
let lens = druid::lens!(Foo, x);
let lens = druid::lens!((u32, bool), 1);
let lens = druid::lens!([u8], [4]);
let lens = druid::lens!(Foo, x.y[5]);