Macro chain_params

macro_rules! chain_params {
    (atomic $atom:ident ; $init:expr ; $t:ty) => { ... };
    (basic $atom:ident ; $init:expr ; $fn_vis:vis , $f:ident ; $t:tt ; $st:tt ; $(#[$($meta:meta)*])*) => { ... };
    (get $struct_vis:vis , $struct_name:ident ; $f:ident ; $(#[$($meta:meta)*])*) => { ... };
    (
		$(#[$($meta:meta)*])* static $atom:ident : _ = _($init:expr);
		$fn_vis:vis fn $f:ident() -> $t:tt;
		$struct_vis:vis struct $struct_name:ident;
		impl Get<_> for _ {}
		$($rest:tt)*
	) => { ... };
    (
		$(#[$($meta:meta)*])* static $atom:ident : $st:tt = _($init:expr);
		$fn_vis:vis fn $f:ident() -> $t:tt;
		$struct_vis:vis struct $struct_name:ident;
		impl Get<_> for _ {}
		$($rest:tt)*
	) => { ... };
    (
		$(#[$($meta:meta)*])* static $atom:ident : _ = _($init:expr);
		$fn_vis:vis fn $f:ident() -> $t:tt;
		$($rest:tt)*
	) => { ... };
    (
		$(#[$($meta:meta)*])* static $atom:ident : $st:tt = _($init:expr);
		$fn_vis:vis fn $f:ident() -> $t:tt;
		$($rest:tt)*
	) => { ... };
    (
		$(#[$($meta:meta)*])* $fn_vis:vis fn $f:ident() -> $t:tt { $fx:expr }
		$struct_vis:vis struct $struct_name:ident;
		impl Get<_> for _ {}
		$($rest:tt)*
	) => { ... };
    (
		$(#[$($meta:meta)*])* $const_vis:vis const $const_name:ident: _ = $cx:expr;
		$fn_vis:vis fn $f:ident() -> $t:tt;
		$struct_vis:vis struct $struct_name:ident;
		impl Get<_> for _ {}
		$($rest:tt)*
	) => { ... };
    () => { ... };
}