As we already seen in a previous chapter we
can use a junction to check if a values is among a given
set of values
Example 7-1. examples/junctions/intro.p6
#!/usr/bin/perl6
my $possible_options = 1|2|3;
print "please give a number(1,2 or 3): ";
my $c = readline;
if ($c == $possible_options) {
say "Correct choice: $c";
} else {
say "Incorrect choice: $c";
}