Macro rand_value

macro_rules! rand_value {
    (@repeat $rng:expr, [$($t:tt)*] $($len:expr)?) => { ... };
    (@array $rng:expr, [$($t:tt)*] $len:expr) => { ... };
    (@tuple $rng:expr, [$([$($args:tt)*])*]) => { ... };
    (@$tag:ident $rng:expr, [[$($args:tt)*]]) => { ... };
    (@$tag:ident $rng:expr, [$($args:tt)*] ($($tuple:tt)*) $($t:tt)*) => { ... };
    (@$tag:ident $rng:expr, [$($args:tt)*] [[$($tt:tt)*]; const $len:expr] $($t:tt)*) => { ... };
    (@$tag:ident $rng:expr, [$($args:tt)*] [[$($tt:tt)*]; $len:expr] $($t:tt)*) => { ... };
    (@$tag:ident $rng:expr, [$($args:tt)*] [($($tt:tt)*); const $len:expr] $($t:tt)*) => { ... };
    (@$tag:ident $rng:expr, [$($args:tt)*] [($($tt:tt)*); $len:expr] $($t:tt)*) => { ... };
    (@$tag:ident $rng:expr, [$($args:tt)*] [$ty:expr; const $len:expr] $($t:tt)*) => { ... };
    (@$tag:ident $rng:expr, [$($args:tt)*] [$ty:expr; $len:expr] $($t:tt)*) => { ... };
    (@$tag:ident $rng:expr, [$($args:tt)*] [$($tt:tt)*] $($t:tt)*) => { ... };
    (@$tag:ident $rng:expr, [$($args:tt)*] $ty:expr) => { ... };
    (@$tag:ident $rng:expr, [$($args:tt)*] $ty:expr, $($t:tt)*) => { ... };
    (@$tag:ident $rng:expr, [$($args:tt)*] , $($t:tt)*) => { ... };
    (@$tag:ident $rng:expr, [$($args:tt)*]) => { ... };
    (seed = $src:expr, $($t:tt)*) => { ... };
    ($rng:expr, $($t:tt)*) => { ... };
}

Return a random value using RandomSpec.