Re: regex transforms of object attributes

If your class lends itself to the technique, you could use an lvalue method and avoid the need to copy anything.

#! perl -slw
use strict;

package Test;

sub new{
    my( $class, $value ) = @_;
    return bless { content => $value }, $class;
}

sub content : lvalue {
    my( $self ) = shift;
    $self->{ content };
}

1;

package main;

my $thing = Test->new( 'empty' );
print $thing->content;

$thing->content = 'the quick brown fox';
print $thing->content;

$thing->content =~ s[\b(.)][\U$1]g;
print $thing->content;
__END__
P:\test>368057
empty
the quick brown fox
The Quick Brown Fox
[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

Comment on Re: regex transforms of object attributes Download Code

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Re^2: regex transforms of object attributes by ambrus (Abbot) on Jun 20, 2004 at 20:20 UTC
BrowserUk, I see a contradiction between your post. In Re^2: regex transforms of object attributes, you say (rightly) that encoding a hash key string in the caller code breaks the encapsulation of the object. Using an lvalue method is, however, almost just as wrong. An lvalue method in Perl cannot do a check on what value you set, or do some computation with the rhs expression (in case the implementation of the attribute changes), so it is IMO not much better than just using a hash key. This is the weakness of the OO support of perl.	[reply]
Re^3: regex transforms of object attributes by BrowserUk (Patriarch) on Jun 20, 2004 at 22:14 UTC
Mostly, I agree with you as I recognised in this thread from a while back--but a couple of self-quotes from my posts in this thread: If your class lends itself to the technique, ... And Of course, if the content has to be verified then using an lvalue sub will also break, but that a different argument entirely:) 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]
Re^3: regex transforms of object attributes by ihb (Deacon) on Jun 20, 2004 at 22:20 UTC
They key difference is that an lvalue method uses a public interface and does not rely on implementation of the object. When choosing to have an lvalue method you choose to have a simple and limited interface, which you argue against, but you're not breaking encapsulation. So there are two different issues. `ihb`	[reply] [d/l]