$\="\n";

sub in { $_ ~~ $_[0]  }


for (qw/abc foo bar 42 unknown/) {
  if    ( in ['abc']) {
    print 'abc';
  }
  elsif ( in [qw/foo bar/] ) {
    print "foo bar";
  }
  elsif ( in [42] ) {
    print "42";
  }
  else {
    print "default: $_";
  }
}

__END__
abc
foo bar
foo bar
42
default: unknown