Oh, you asked for it!

Mark-Jason Dominus presented this at the Perl Conference. It's a generic way to evaluate a Perl expression inside a double-quoted string:

package Eval;

sub import
{
    my ($package, $name) = @_;
    $name = 'Eval' unless defined $name;
    my %magical_hash;
    tie %magical_hash =>Eval;
    my $caller = caller;
    
    *{caller . '::' . $name} = \%magical_hash;
}

sub TIEHASH
{
    my $self = \'fake';
    bless $self => Eval;
}

sub FETCH 
{
    my ($self, $value) = @_;
    $value;
}

[download]

Looks pretty freaky, eh? Okay, now try this:

use Eval => ':';

$salary = 43_000;
print "After your raise, you will make $:{$salary*1.06}.\n";

[download]

Yeek. Have fun!

In reply to RE: Re: How Does Interpolation Work? (CMonster: method call eval) by CMonster
in thread How Does Interpolation Work? by Anonymous Monk

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