Even with jeffa's notes below, it still took me a while to wrap this around my brain but when I had, I came up with this....

my @array = qw /a b c d e f/;
my $hash;
my $val = 1;
($hash->{pop @array}, $val, $hash) = ($val, $hash, undef) while @array
+;
$hash = $val;
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Which is slightly cleaner?, but that final assignment stood out so...

my @array = qw /a b c d e f/;
my $hash = 1;
my $tmp;

($tmp->{pop @array}, $hash, $tmp) = ($hash, $tmp, undef)  while @array
+;
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Slightly non-intuative to assign the value to the hashref at the start but...

my @array = qw /a b c/;
my %hash = map {$_ => 1} @array;
return \%hash;
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can that be done with a map and a hashref rather than having to return a hashref? ripped off from tadman in Re: an easier way with grep, map, and/or sort?.
--au

return {map {$_ => 1} qw /a b c/}
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Or did I understand your questing wrong?

Abigail