Can't use a label for a block.

[Kray-G]

A label for a block is not available with compile error.

var a = 10;
LABEL: {
Error: syntax error near the <(unknown)>:2
    a = 20;
    while (1) {
        break LABEL if (++a == 50);
    }
    a = 100;
}
System.println("a = %{a}"); // a = 50

[Kray-G]

I got it's not possible to solve it with this style because of a syntax conflict.
I have to change the specification about this label style...

[Kray-G]

I changed a specification for a label to be with two colons.
It's okay with 1 colon as well for a backward compatible, but a colon should be needed twice only for a block.