Macro rosenpass::data_lense

macro_rules! data_lense {
    (token_muncher_ref @ $offset:expr ; $( $attr:meta )* ; $field:ident : $len:expr $(, $( $tail:tt )+ )?) => { ... };
    (token_muncher_mut @ $offset:expr ; $( $attr:meta )* ; $field:ident : $len:expr $(, $( $tail:tt )+ )?) => { ... };
    (maybe_docstring_link $x:literal) => { ... };
    (maybe_docstring_link $x:expr) => { ... };
    ($type:ident $( < $( $generic:ident ),+ > )? := $( $( #[ $attr:meta ] )* $field:ident : $len:expr ),+) => { ... };
}

A macro to create data lenses. Refer to the msgs mod for an example and further elaboration