Mastering Modern Perl: Writing Efficient and Maintainable Code/

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Indirect Objects

Indirect Objects

Learn when to avoid using indirect objects and why.

We'll cover the following...

Perl isn't a pure object-oriented language. It has no operator new; a constructor is anything that returns an object. By convention, constructors are class methods named new(), but we can name these methods anything we want or even use functions. Several old Perl OO tutorials promote the use of C++ and Java-style constructor calls:

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package Alces {
    use Moose;
}
my $q = new Alces; # DO NOT USE

However, they could use the obvious method call:

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package Alces {
    use Moose;
}
my $q = Alces->new;

These examples produce equivalent behavior, except when they don’t.

Bareword indirect invocations

In the indirect object form (more precisely, the dative case) of the first example, the method precedes the invocant. This is fine in spoken languages where verbs and nouns are ...