Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

I normally use references in the most basic way--like passing hashes or arrays to subroutines by reference. I've been using Net::LDAP extensively for over a year and just today noticed the as_struct() method of Net::LDAP::Search.

This method seems save considerable code as opposed to the entries() method. When using entries(), I end up creating my own HoHs via $entry->get_value( 'attribute' ). The only nice thing about building my own HoH is that I'm comfortable using $hash{dn}{mail} constructs. Using the as_struct() method means using either @{ $$href{$dn}{mail} } or @{ $hash{$dn}{mail} }.

Is there a shorthand notation for the above or am I making too big a deal out of using the extra outer @{} constructs? I looked closely at References quick reference but don't grok all of it.

Thanks.

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Re: Reference Notation
by BrowserUk (Patriarch) on Jul 16, 2004 at 06:47 UTC

    Assuming that $href->{$dn}->{$mail} contains an array reference, then your choices are: 

    @{ $$href{dn}{mail} };
# or 
@{ $href->{dn}{mail} }; 
# or 
@{ $href->{dn}->{mail} };

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    to refer to the whole array and 

    $$href{$dn}{mail}[0];
# or 
$href->{dn}{mail}[0];
# or
$href->{dn}->{mail}->[0]; ## yawn! :)
# or ...

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    to refer to the individual elements.

    However, there is a useful though slightly obscure way of simplifying the access to deeply nested structures without needing to copy data into temporary variables. 

    ## Make the localised glob *mail 
## act as an alias to the nested array

{
    local *mail = $ref->{dn}{mail}; 
    print @mail; ## Print the whole array
    print $mail[0]; ## The first element
} 
## *mail reverts to it's old value here.

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    It's especially useful when you have to do a whole bunch of accesses to the elements of some deeply nested structureal element.

    Examine what is said, not who speaks.
    "Efficiency is intelligent laziness." -David Dunham
    "Think for yourself!" - Abigail
    "Memory, processor, disk in that order on the hardware side. Algorithm, algoritm, algorithm on the code side." - tachyon
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      Whats the benifit of a glob like that as opposed to a reference? Since it contains an array ref couldn't you just do. my $mail = $ref->{dn}{mail}; print @$mail;


      ___________
      Eric Hodges
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        The benefits are @mail -v- @$mail and $mail[ 0 ] -v- $mail->[ 0 ], if the array contains just scalars, Where it really comes into it's own is if the array contains further nested structures. 

        local *mail = ...
$mail[ 3 ]{ recipient } = $mail[ 2 ]{ sender };

## is easier on the eyes and fingers than

$mail->[ 3 ]{ recipient } = $mail->[ 2 ]{ sender };

        [download]
        Examine what is said, not who speaks.
        "Efficiency is intelligent laziness." -David Dunham
        "Think for yourself!" - Abigail
        "Memory, processor, disk in that order on the hardware side. Algorithm, algoritm, algorithm on the code side." - tachyon
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