Usually when you need this is when you have multiple depths of references and the syntax becomes ambiguous to the interpreter. Something like,
@{$hashref->{$scalar}}
In this case without the {} the interpreter can't tell if you mean,
Yes, the interpreter can tell because of precedence. @$hashref->{$scalar} is the same as @{$hashref}->{$scalar} which in this case will produce an error.
(@$hashref) ->{$scalar} or @ ( $hashref->{$scalar} )
The parens are NOT normal syntax, I am using them to show grouping.
perldoc perldsc [snip] CAVEAT ON PRECEDENCE Speaking of things like "@{$AoA[$i]}", the following are actually the same thing:
$aref->[2][2] # clear
$$aref[2][2] # confusing That's because Perl's precedence rules on its five prefix dereferencers
(which look like someone swearing: "$ @ * % &") make them bind more
tightly than the postfix subscripting brackets or braces! This will no
doubt come as a great shock to the C or C++ programmer, who is quite
accustomed to using *a[i] to mean what's pointed to by the i'th element
of "a". That is, they first take the subscript, and only then deref-
erence the thing at that subscript. That's fine in C, but this isn't C. The seemingly equivalent construct in Perl, $$aref[$i] first does the
deref of $aref, making it take $aref as a reference to an array, and then
dereference that, and finally tell you the i'th value of the array
pointed to by $AoA. If you wanted the C notion, you'd have to write
"${$AoA[$i]}" to force the $AoA[$i] to get evaluated first before the
leading "$" dereferencer.John -- use Perl; program fulfillment
-- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] <http://learn.perl.org/> <http://learn.perl.org/first-response>
