Macro proconio::input

macro_rules! input {
    (from $source:expr $(,)?) => { ... };
    (from $source:expr, mut $var:ident: $kind:tt $($rest:tt)*) => { ... };
    (from $source:expr, $var:ident: $kind:tt $($rest:tt)*) => { ... };
    ($($rest:tt)*) => { ... };
}

read input from stdin.

basic syntax is:

input! {
    from source,          // optional: if you omitted, stdin is used by default.
    (mut) variable: type, // mut is optional: mut makes the variable mutable.
    ...
}

the trailing comma is optional. source can be anything implementing Source. This macro moves out the specified source. If you want to prevent moving, you can use &mut source since &mut S where S: Source also implements Source.

Note: for macro matcher's limitation, only a single token tree (i32, [T; n], (T, U) or etc) is accepted by type. This means you can't use generics YourType<T> as the type. To use such a type, you can alias it like type YourTypeT = YourType<T> to make it a single token tree. (This is why Chars and Bytes exists. They are simply alias of Vec<char> and Vec<u8>.)