Macro druid::lens

macro_rules! lens {
    ($ty:ty, [$index:expr]) => { ... };
    ($ty:ty, $field:tt) => { ... };
}

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: u32 }
let lens = druid::lens!(Foo, x);
let lens = druid::lens!((u32, bool), 1);
let lens = druid::lens!([u8], [4]);