Macro scan_value 

macro_rules! scan_value {
    (@repeat $scanner:expr, [$($t:tt)*] $len:expr) => { ... };
    (@repeat $scanner:expr, [$($t:tt)*]) => { ... };
    (@iter $scanner:expr, [$($t:tt)*] $len:expr) => { ... };
    (@array $scanner:expr, [$($t:tt)*] $len:expr) => { ... };
    (@tuple $scanner:expr, [$([$($args:tt)*])*]) => { ... };
    (@sparen $scanner:expr, [] @$e:expr; $($t:tt)*) => { ... };
    (@sparen $scanner:expr, [] ($($tt:tt)*); $($t:tt)*) => { ... };
    (@sparen $scanner:expr, [] [$($tt:tt)*]; $($t:tt)*) => { ... };
    (@sparen $scanner:expr, [] $ty:ty = $e:expr; $($t:tt)*) => { ... };
    (@sparen $scanner:expr, [] $ty:ty; $($t:tt)*) => { ... };
    (@sparen $scanner:expr, [] $($args:tt)*) => { ... };
    (@sparen $scanner:expr, [$($args:tt)+] const $len:expr) => { ... };
    (@sparen $scanner:expr, [$($args:tt)+] iter $len:expr) => { ... };
    (@sparen $scanner:expr, [$($args:tt)+] $len:expr) => { ... };
    (@$tag:ident $scanner:expr, [[$($args:tt)*]]) => { ... };
    (@$tag:ident $scanner:expr, [$($args:tt)*] @$e:expr $(, $($t:tt)*)?) => { ... };
    (@$tag:ident $scanner:expr, [$($args:tt)*] ($($tuple:tt)*) $($t:tt)*) => { ... };
    (@$tag:ident $scanner:expr, [$($args:tt)*] [$($tt:tt)*] $($t:tt)*) => { ... };
    (@$tag:ident $scanner:expr, [$($args:tt)*] &str $(, $($t:tt)*)?) => { ... };
    (@$tag:ident $scanner:expr, [$($args:tt)*] $ty:ty = $e:expr $(, $($t:tt)*)?) => { ... };
    (@$tag:ident $scanner:expr, [$($args:tt)*] $ty:ty $(, $($t:tt)*)?) => { ... };
    (@$tag:ident $scanner:expr, [$($args:tt)*] , $($t:tt)*) => { ... };
    (@$tag:ident $scanner:expr, [$($args:tt)*]) => { ... };
    (src = $src:expr, $($t:tt)*) => { ... };
    (iter = $iter:expr, $($t:tt)*) => { ... };
    ($scanner:expr, $($t:tt)*) => { ... };
}

scan a value with Scanner

• scan_value!(scanner, ELEMENT)

ELEMENT :=

• $ty: Scan
• &str: borrowed token; the source stays borrowed until its last use
• @$expr: MarkedScan
• $ty = $expr: MarkedScan
• [ELEMENT; $expr]: vector
• [ELEMENT; const $expr]: array
• [ELEMENT]: iterator
• [ELEMENT; iter $expr]: iterator of the specified length
• ($(ELEMENT)*,): tuple