Macro arg

macro_rules! arg {
    ($args:ident: @push $arg:expr) => { ... };
    ($args:ident: @map $arg:expr) => { ... };
    ($args:ident: @extend $arg:expr) => { ... };
    ($args:ident: @maps $arg:expr) => { ... };
    ($args:ident: $arg:expr) => { ... };
}