Optional

The names of the product elements.

The name of the type.

Composes an optional with a lens. The same as first(second).

Composes an optional with a prism. The same as first(second).

Composes two optionals. The same as first(second).

Composes a lens with a prism. The same as first(second).

Composes a lens with an optional. The same as first(second).

Composes a prism with a lens. The same as first(second).

Composes a prism with an optional. The same as first(second).

Creates an optional on the element at index of a sequence. A sequence with index elements or fewer has no focus (OpticCheck.SequenceIndexOutOfBounds).

Creates an optional on the value at key in a map. A map without key has no focus (OpticCheck.MissingKey), and replace does not add the key.

Creates an optional on the value inside a wrapper, such as a schema built with Schema#transform. It reads with the wrapper's unwrap and writes with its wrap. When either throws a SchemaError, the focus counts as missing (OpticCheck.WrappingError); other exceptions propagate.