rovv

rovv is a crate to provide anonymous row type, which fields can be access by lens-rs

Example

A row with field a: String

```rust fn withfielda(r: row! { a: String, .. }) -> String { r.view(optics!(a)) }

fn tofielda() -> row! { a: String, .. } { Bar { a: "this is Bar".to_string(), c: 0, } }

let foo = Foo { a: "this is Foo".tostring(), b: (), }; let bar = Bar { a: "this is Bar".tostring(), c: 0, };

asserteq!(withfielda(foo.clone()).asstr(), "this is Foo"); asserteq!(withfielda(bar.clone()).asstr(), "this is Bar"); ```

A row may have field Some: String

rust row! { Some: String?, .. } dyn_row! { Some: String?, .. } // dynamic version of row!

A row have multiple fields _mapped: String

rust row! { _mapped: String*, .. } dyn_row! { _mapped: String*, .. }

A row with a mutable or immutable field:

rust row! { ref a: A, mut b: B, .. } dyn_row! { ref a: A, mut b: B, .. }

A row bound by lifetimes 'a

rust row! { <'a> ref a: A, mut b: B, .. } dyn_row! { <'a> ref a: A, mut b: B, .. }

In fact,

• row! { <'a> ref a: A, mut b: B, c: C, .. } is impl LensRef<Optic![a], Image = A> + LensMut<Optic![b], Image = B> + Lens<Optic![c], Image = C> + 'a
• dyn_row! { <'a> ref a: A, mut b: B, c: C, .. } is dyn LensRef<Optic![a], Image = A> + LensMut<Optic![b], Image = B> + Lens<Optic![c], Image = C> + 'a

There are some magic in dyn_row!, so please don't forget toml [package.metadata.inwelling] rovv = true in Cargo.toml