Hi, I am trying to solve an object initialisation problem: suppose this is my object constructor:

sub new { 
    my ($pkg) = $_[0];
    my $this = bless { data => $_[1], }, $pkg;
    return $this;
}
[download]

The non-trivial argument ($_[1], a scalar) passed to the constructor can be a VERY large buffer, and I want to store it into the object. I have the following constraints:

• there must NEVER be, at any time, two copies of this buffer (because it is very memory-expensive)
• $this->{data} must have scalar semantics, i.e. I don't want to save a reference
• The piece of code invoking the constructor must not be able to access the buffer through the actual argument after the invocation

Ideally, the best solution should be an operator like swap $a, $b, exchanging the underlying data objects "pointed to" by the two scalars $a and $b. In this way I could initialise $this->{data} to, say, a null string, and then exchange its value with that of $_[1].

I was able to find the module Data::Swap on CPAN, which does exactly this, but I would like to know if this can be done natively in Perl.

Thanks to everybody in advance,
Stefano.

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