scan_rules::readln!

macro_rules! readln {
    ($($rules:tt)*) => { ... };
}

Reads a line of text from standard input, then scans it using the provided rules. The result of the readln! invocation is the type of the rule bodies; just as with match, all bodies must agree on their result type.

Note that this macro automatically flushes standard output. As a result, if you use this macro while you are holding a lock on standard output, your program will deadlock.

If you wish to read from standard input whilst manually locking standard output, you should use scan! directly.

See also: Pattern Syntax, try_readln!.

Panics

Panics if an error is encountered while reading from standard input, or if all rules fail to match.