G'day Bod,

I was certain that at some point I saw the rules for this but I'm buggered if I can now find that doco. The rules for the LHS of => (see perlop: Comma Operator) are almost (if not exactly) the same: use that as a guide.

LanX showed key() and (key); you can also use a unary plus, i.e. +key (which is what I tend to use more often than not). Consider these:

$ perl -E '
    use constant X => "a";
    sub Y {"b"}
    my %h = qw{a 1 b 2 X 24 Y 25};
    say for $h{X}, $h{"X"}, $h{+X}, $h{X()}, $h{(X)};
    say for $h{Y}, $h{"Y"}, $h{+Y}, $h{Y()}, $h{(Y)};
'
24
24
1
1
1
25
25
2
2
2
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If the key looks even vaguely ambiguous, I will quote it; otherwise, I rarely do.