Macro cryptol 

macro_rules! cryptol {
    (
        path $path:expr;

        $(#[$attr:meta])*
        $pub_:vis fn $name:ident
                ( $($arg_name:ident : $arg_ty:ty),* )
                $( -> $ret_ty:ty )?
                $(= $cryptol_name:expr)? ;
        $($rest:tt)*
    ) => { ... };
    (
        path $path:expr;

        $(#[$attr:meta])*
        $pub_:vis fn $name:ident
                < $(const $N:ident: $N_ty:ty),* >
                ( $($arg_name:ident : $arg_ty:ty),* )
                $( -> $ret_ty:ty )?
                = $cryptol_name:expr ;
        $($rest:tt)*
    ) => { ... };
    (
        path $path:expr;
    ) => { ... };
}