restor
macro_rules! err { ($e:expr) => { ... }; ($e:expr, $other:expr) => { ... }; ($e:expr, $other:expr, *) => { ... }; ($e:expr, $other:expr, [i]) => { ... }; }
A shorthand for unwrapping a Result into an Err(x).
Result
Err(x)
The following syntaxes do the following:
(expr)
x
(expr, val)
x == val; x
(expr, val, *)
*x == val; x
(expr, val, [ind])
x[ind] == val; x