>perl -E"say 'ok' if 'a' ~~ ('a', 'b');"

>perl -E"say 'ok' if 'b' ~~ ('a', 'b');"
ok

##</code><code>##

say "ok" if "a" ~~ X;

##</code><code>##

say "ok" if "a" ~~ scalar(X);

##</code><code>##

>perl -E"use constant X => qw(a b c); say 'ok' if 'a' ~~ @{[ X ]}"
ok