From: Chap Harrison <c...@pobox.com>
> Let me break this expression down according to my current understanding.
>
> @{$hash{adams...@keys} = @values;
>
> parses as follows:
>
> adams : short for 'adams', a string literal, being used as a hash key
> $hash{adams} : the value in the hash associated with 'adams', a scalar
> (always), and a ref to a hash in this case
> {$hash{adams}} : extra braces, used to force correct "binding" (?)
> with surrounding context, I expect.
> {$hash{adams...@keys} : the hashref is dereferenced, and a set of keys
> (provided by an array) is looked up in the hash, resulting in a set of
> values; or, more precisely, *aliases* of values.
> @{$hash{adams...@keys} : an array of aliases of the hash values
> associated with the keys supplied in @keys.
> @{$hash{adams...@keys} = @values : behaves much like...
>
> ( $hash{adams}{a}, $hash{adams}{ar}, $hash{adams}{af}, $hash{adams}
> {aw} ) = ( 1, 19, 13, 11 )
That's prettymuch it, except that it's not an array of aliases, but
LIST of aliases. The difference is subtle, but important.
See http://perldoc.perl.org/perlfaq4.html#What-is-the-difference-
between-a-list-and-an-array%3f and
http://www.perlmonks.org/?node_id=130861
And it doesn't really make sense to add only the {...@keys} without the
@. You have to consider them both at the same time, because the sigil
you use affects how is the @keys evaluated!
See
%hash = (a => 999, b => 888, c => 777, d => 666, 3 => 123456);
@keys = ('a','b','c');
print $ha...@keys},"\n";
print @ha...@keys},"\n";
$href = \%hash;
print ${$hre...@keys},"\n";
print @{$hre...@keys},"\n";
HTH, Jenda
===== je...@krynicky.cz === http://Jenda.Krynicky.cz =====
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