Re: Reference Notation

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

Comment on Re: Reference Notation Select or Download Code

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Re^2: Reference Notation by eric256 (Parson) on Jul 16, 2004 at 19:05 UTC
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	[reply] [d/l]
Re^3: Reference Notation by BrowserUk (Patriarch) on Jul 16, 2004 at 19:16 UTC
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 } = $mail->[ 2 ]{ sender };` [download] Examine what is said, not who speaks. "Efficiency is intelligent laziness." -David Dunham "Think for yourself!" - Abigail "Memory, processor, disk in that order on the hardware side. Algorithm, algoritm, algorithm on the code side." - tachyon	[reply] [d/l] [select]
Re^4: Reference Notation by eric256 (Parson) on Jul 16, 2004 at 22:37 UTC
Maybe your eyes :) Mine like `$mail->[3]->{recipient} = $mail->[2]->{recipient};` but that might be a flaw of mine. Cool to know that you can glob a @array onto an array reference though. ___________ Eric Hodges	[reply] [d/l]


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