Macro spirt::transform::transform

macro_rules! transform {
    ({ $($input:ident -> $input_transformed:expr),+ $(,)? } => $output:expr) => { ... };
}

Helper macro to create a combined Transformed out of several variables, each with their own transformation, where any Transformed::Changed input will result in a Transformed::Changed output, using a combination of the changed inputs, and clones of the unchanged inputs.