Macro tensor_macros::make_index_fn

macro_rules! make_index_fn {
    ($name:ident; $dim:literal) => { ... };
    ($name:ident; $($dims:literal),+) => { ... };
    ($name:ident; $dim:literal $(,$dims:literal)*; $($i:ident),*; $($t:ty),*; $($dims_bk:literal),*) => { ... };
    ($name:ident; ; $($i:ident),*; $($t:ty),*; $($dims:literal),*) => { ... };
}