Macro syakutori

macro_rules! syakutori {
    (
        $n:expr,
        ($l:ident, $r:ident),
        |$i:ident| $addable:expr,
        |$j:ident| $add:expr,
        |$k:ident| $remove:expr,
        $show:expr $(,)?
    ) => { ... };
}

arg:

• n: length of array
• (l, r): ident of left-bound and right-bound
• addable: |index| expr: return is addable element
• add: |index| expr: add element
• remove: |index| expr: remove element
• show: call n times for l in 0..n, with rightmost r