Macro args

macro_rules! args {
    (
    $args:ident: if let $pat:pat = $ok:expr =>
    $(@$oper:ident)? $arg:expr $(; $($rest:tt)*)?
  ) => { ... };
    (
    $args:ident: if $condition:expr =>
    $(@$oper:ident)? $arg:expr $(; $($rest:tt)*)?
  ) => { ... };
    (
    $args:ident: let $pat:pat = $ok:expr =>
    $(@$oper:ident)? $arg:expr $(; $($rest:tt)*)?
  ) => { ... };
    ($args:ident: $(@$oper:ident)? $arg:expr $(; $($rest:tt)*)?) => { ... };
    ($args:ident: ) => { ... };
}