as<$C> method

$C as<$C>(
  1. $C copy(
    1. In,
    2. Then<In, Out> ,
    3. Then<Out, Result>
    )
)

Implementation

$C as<$C>($C Function(In, Then<In, Out>, Then<Out, Result>) copy) =>
    copy($value, $then1, $then2);