Macro fuel_types::mem_layout

macro_rules! mem_layout {
    () => { ... };
    (@accum () -> ($s:ident for $o:ident $($f:ident: $t:ty = $si:expr, $a:expr);*) -> ($($addr:tt)*)) => { ... };
    (@accum ($field:ident: $t:ty = $size:expr, $($tail:tt)*) -> ($s:ident for $o:ident $($f:ident: $typ:ty = $si:expr, $a:expr);*) -> ($($addr:tt)*)) => { ... };
    (@as_expr ($s:ident $o:ident $($field:ident, $size:expr, $t:ty, $addr:expr)+) -> ($($len:tt)*)) => { ... };
    ($s:ident for $o:ident $field:ident: $t:ty = $size:expr, $($tail:tt)*) => { ... };
}

Defines a memory layout for a type. The address starts at 0 and is incremented by the size of each field. The syntax is field_name: field_type = field_size_in_bytes, ....